U.S. patent application number 12/651019 was filed with the patent office on 2011-06-30 for positioning system and positioning method.
This patent application is currently assigned to POLARIS WIRELESS, INC.. Invention is credited to Tarun Kumar Bhattacharya, Hassan M. El-Sallabi, Scot Douglas Gordon, Yasuhiro Oda, Jiyun Shen.
Application Number | 20110156952 12/651019 |
Document ID | / |
Family ID | 44186836 |
Filed Date | 2011-06-30 |
United States Patent
Application |
20110156952 |
Kind Code |
A1 |
Bhattacharya; Tarun Kumar ;
et al. |
June 30, 2011 |
Positioning System and Positioning Method
Abstract
It is an object of the present invention to perform positioning
at the proper positioning time and positioning precision in
response to a requirement with respect to positioning. A
positioning server 10 comprises a first positioning component 12
that performs positioning of a cellular terminal 20 by a hybrid
algorithm 1, in which indoor/outdoor determination is performed on
the basis of reception state information indicating the reception
state at the cellular terminal 20, and in which an end condition is
determined on the basis of the result of the indoor/outdoor
determination; and a second positioning component 13 that performs
positioning of the cellular terminal 20 by a hybrid algorithm 2, in
which the approximate position of the cellular terminal 20 is
calculated on the basis of reception state information indicating
the reception state at the cellular terminal 20, and in which
whether or not to end the positioning of the cellular terminal 20
is decided on the basis of the precision of the approximated
position.
Inventors: |
Bhattacharya; Tarun Kumar;
(San Jose, CA) ; El-Sallabi; Hassan M.; (Palo
Alto, CA) ; Gordon; Scot Douglas; (Redmond, WA)
; Oda; Yasuhiro; (Kanagawa, JP) ; Shen; Jiyun;
(Kanagawa, JP) |
Assignee: |
POLARIS WIRELESS, INC.
Santa Clara
CA
NTT DoCoMo, Inc.
Tokyo
|
Family ID: |
44186836 |
Appl. No.: |
12/651019 |
Filed: |
December 31, 2009 |
Current U.S.
Class: |
342/357.31 |
Current CPC
Class: |
G01S 5/0252 20130101;
G01S 19/48 20130101 |
Class at
Publication: |
342/357.31 |
International
Class: |
G01S 19/48 20100101
G01S019/48 |
Claims
1. A positioning system for estimating the position of a receiver
that has a wireless communication function and a receiving function
for signals used in GPS positioning, the system comprising: first
positioning means for estimating the position of the receiver by a
first positioning method; second positioning means for estimating
the position of the receiver by a second positioning method;
requirement information input means for inputting requirement
information indicating a requirement with respect to estimation of
the position of the receiver; and positioning method determination
means for determining whether to execute the first or second
positioning method on the basis of the requirement information
inputted by the requirement information input means, and causing
the first positioning means or the second positioning means to
execute the estimation of the position of the receiver by the
determined positioning method, wherein the first positioning means
comprises: first reception state information acquisition means for
acquiring reception state information indicating the reception
state of a radio wave by the wireless communication function in the
receiver; first position estimation means for estimating the
position of the receiver on the basis of the reception state
information acquired by the first reception state information
acquisition means, and performing GPS positioning of the receiver
on the basis of the reception state of a signal used in GPS
positioning and received by the receiver; first end decision means
for deciding whether or not to end the estimation of the position
of the receiver by the first position estimation means on the basis
of a specific end condition, and if it is decided not to end,
causing the first position estimation means to estimate the
position of the receiver also on the basis of new reception state
information acquired by the first reception state information
acquisition means at a different timing from that of the reception
state information used to estimate the position by the first
position estimation means, and deciding whether or not to end the
position estimation by the first position estimation means also on
the basis of whether or not GPS positioning by the first position
estimation means has been ended; first indoor/outdoor determination
means for determining whether the receiver is indoors or outdoors
on the basis of the reception state information acquired by the
first reception state information acquisition means; and first end
condition determination means for determining the specific end
condition on the basis of the result of determination by the first
indoor/outdoor determination means, and the second positioning
means comprises: second reception state information acquisition
means for acquiring reception state information indicating the
reception state of the radio wave by the wireless communication
function in the receiver; second approximate position estimation
means for estimating an approximate position of the receiver on the
basis of the reception state information acquired by the second
reception state information acquisition means, and calculating the
precision of the approximate position; second end decision means
for deciding whether or not to end the estimation of the position
of the receiver on the basis of the precision calculated by the
second approximate position estimation means, and if it is decided
to end, ending the estimation of the position of the receiver by
using the approximate position estimated by the second approximate
position estimation means as the position of the receiver; second
indoor/outdoor determination means for determining whether the
receiver is indoors or outdoors on the basis of the reception state
information acquired by the second reception state information
acquisition means; and second positioning control means for
controlling the execution of GPS positioning of the receiver on the
basis of the result of decision by the second end decision means
and the result of determination by the second indoor/outdoor
determination means.
2. The positioning system according to claim 1, wherein the first
end condition determination means determines the specific end
condition also on the basis of the requirement information inputted
by the requirement information input means.
3. The positioning system according to claim 1, wherein the first
end condition determination means acquires environment information
indicating the environment in which the receiver is placed, and
determines the specific end condition also on the basis of the
environment information.
4. The positioning system according to claim 1, wherein the first
reception state information acquisition means acquires strength
information indicating the reception strength corresponding to an
emission source of the radio wave as the reception state
information, and the first position estimation means estimates the
position of the receiver by storing in advance information
indicating the relation between the position and reception strength
of the radio wave corresponding to an emission source of the radio
wave, and by comparing the strength information acquired by the
first reception state information acquisition means with the
information stored in advance.
5. The positioning system according to claim 1, wherein the first
end condition determination means determines a threshold of
positioning result error and/or an elapsed time of positioning as
the specific end condition.
6. The positioning system according to claim 1, further comprising
emission source positioning means for acquiring information
indicating the size of a communication area of an emission source
of the radio wave received by the receiver, estimating the position
of the receiver on the basis of the size of the communication area,
and deciding whether or not to cause the first positioning means or
second positioning means to execute the estimation of the position
of the receiver.
7. The positioning system according to claim 1, wherein the second
positioning control means controls the execution of positioning
that estimates the position of the receiver on the basis of the
result of decision by the second end decision means and the result
of determination by the second indoor/outdoor determination means
and also on the basis of new reception state information acquired
by the second reception state information acquisition means, at a
timing that differs from that of the reception state information
used to estimate the approximate position by the second approximate
position estimation means.
8. The positioning system according to claim 7, wherein the
reception state information acquisition means acquires strength
information indicating the reception strength corresponding to an
emission source of the radio wave as the reception state
information, and the estimation of the approximate position by the
approximate position estimation means and the estimation of the
position of the receiver which uses the reception state information
and the execution of which is controlled by the positioning control
means, are carried out by a method in which the position of the
receiver is estimated by storing in advance information indicating
the relation between the position and reception strength of the
radio wave corresponding to the emission source of the radio wave,
and by comparing the strength information acquired by the reception
state information acquisition means with the information stored in
advance.
9. A positioning method for estimating the position of a receiver
that has a wireless communication function and a receiving function
for signals used in GPS positioning, the method comprising: a first
positioning step of estimating the position of the receiver by a
first positioning method; a second positioning step of estimating
the position of the receiver by a second positioning method; a
requirement information input step of inputting requirement
information indicating a requirement with respect to estimation of
the position of the receiver; and a positioning method
determination step of determining whether to execute the first or
second positioning method on the basis of the requirement
information inputted in the requirement information input step, and
executing the estimation of the position of the receiver by the
determined positioning method in the first positioning step or the
second positioning step, wherein the first positioning step
comprises: a first reception state information acquisition step of
acquiring reception state information indicating the reception
state of a radio wave by the wireless communication function in the
receiver; a first position estimation step of estimating the
position of the receiver on the basis of the reception state
information acquired in the first reception state information
acquisition step, and performing GPS positioning of the receiver on
the basis of the reception state of a signal used in GPS
positioning and received by the receiver; a first end decision step
of deciding whether or not to end the estimation of the position of
the receiver in the first position estimation step on the basis of
a specific end condition, and if it is decided not to end,
estimating the position of the receiver in the first position
estimation step also on the basis of new reception state
information acquired in the first reception state information
acquisition step at a different timing from that of the reception
state information used to estimate the position in the first
position estimation step, and deciding whether or not to end the
position estimation in the first position estimation step also on
the basis of whether or not GPS positioning in the first position
estimation step has been ended; a first indoor/outdoor
determination step of determining whether the receiver is indoors
or outdoors on the basis of the reception state information
acquired in the first reception state information acquisition step;
and a first end condition determination step of determining the
specific end condition on the basis of the result of determination
in the first indoor/outdoor determination step, and the second
positioning step comprises: a second reception state information
acquisition step of acquiring reception state information
indicating the reception state of the radio wave by the wireless
communication function in the receiver; a second approximate
position estimation step of estimating an approximate position of
the receiver on the basis of the reception state information
acquired in the second reception state information acquisition
step, and calculating the precision of the approximate position; a
second end decision step of deciding whether or not to end the
estimation of the position of the receiver on the basis of the
precision calculated in the second approximate position estimation
step, and if it is decided to end, ending the estimation of the
position of the receiver by using the approximate position
estimated in the second approximate position estimation step as the
position of the receiver; a second indoor/outdoor determination
step of determining whether the receiver is indoors or outdoors on
the basis of the reception state information acquired in the second
reception state information acquisition step; and a second
positioning control step of controlling the execution of GPS
positioning of the receiver on the basis of the result of decision
in the second end decision step and the result of determination in
the second indoor/outdoor determination step.
10. A method comprising: (a) estimating whether or not a wireless
terminal is indoors; (b) when said wireless terminal is estimated
to be indoors, estimating the location of said wireless terminal
via a first technique, and otherwise, estimating the location of
said wireless terminal via a second technique; and (c) transmitting
the estimated location.
11. The method of claim 10 wherein said second technique is
performed by said wireless terminal, and wherein said first
technique is not performed by said wireless terminal.
12. The method of claim 10 wherein said first technique is
performed by said wireless terminal, and wherein said second
technique is not performed by said wireless terminal.
13. The method of claim 10 wherein said first technique is based on
pattern matching one or more signal strengths as received at said
wireless terminal, and wherein said second technique is based on
the Global Positioning System.
14. The method of claim 13 further comprising halting reception of
Global Positioning System signals when said wireless terminal is
estimated to be indoors.
15. A method comprising: selecting one of a plurality of algorithms
for estimating the location of a wireless terminal, wherein the
selection is based, at least in part, on a requirement pertaining
to power consumption at said wireless terminal; estimating the
location of said wireless terminal via the selected algorithm; and
transmitting the estimated location.
16. The method of claim 15 wherein the selection is also based on
an estimate of whether said wireless terminal is located in an
urban environment.
17. The method of claim 15 wherein the selection is also based on
an estimate of whether said wireless terminal is located in a
suburban environment.
18. The method of claim 15 wherein the selection is also based on
an estimate of whether said wireless terminal is located in a rural
environment.
19. The method of claim 15 wherein at least one of said plurality
of algorithms comprises performing a first technique and a second
technique concurrently.
20. The method of claim 19 wherein said first technique is
performed by said wireless terminal, and wherein said second
technique is not performed by said wireless terminal.
21. The method of claim 20 wherein said first technique is based on
the Global Positioning System, and wherein said second technique is
based on pattern matching one or more signal strengths as received
at said wireless terminal.
22. The method of claim 15 wherein at least one of said plurality
of algorithms comprises performing exactly one of a first technique
and a second technique.
23. The method of claim 15 wherein the selection is also based on a
time requirement.
24. The method of claim 15 wherein the selection is also based on
an accuracy requirement.
25. The method of claim 15 wherein the selection is also based on
the energy level of said wireless terminal's battery.
26. A method comprising: (a) receiving a time requirement for
locating a wireless terminal; (b) when said time requirement
specifies a first condition, estimating the location of said
wireless terminal by performing a first technique and a second
technique concurrently, and when said time requirement specifies a
second condition, estimating the location of said wireless terminal
by performing exactly one of said first technique and said second
technique; and (c) transmitting the estimated location.
27. The method of claim 26 wherein when said time requirement
specifies said second condition, which of said first technique and
said second technique is performed is based on an estimation of
whether or not said wireless terminal is indoors.
28. The method of claim 26 wherein said first technique is
performed by said wireless terminal, and wherein said second
technique is not performed by said wireless terminal.
29. The method of claim 28 wherein said first technique is based on
the Global Positioning System, and wherein said second technique is
based on pattern matching one or more signal strengths as received
at said wireless terminal.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a positioning system and a
positioning method for estimating the position of a receiver.
[0003] 2. Related Background Art
[0004] There has been proposed in the past a technique for
estimating the position of a cellular terminal (mobile
communication terminal) or other such receiver on the basis of the
reception strength (reception level) of the radio wave received by
the receiver. Japanese Patent Application No. H7-231473, which is a
Japanese laid-open patent application, discusses a technique for
estimating the position of a receiver by taking information
indicating the relation between the reception strength of a radio
wave received from a specific base station and the position at
which this radio wave was received, storing this information in a
database, and using this database to match with reception
strength.
[0005] Also known in the past was a technique for using a GPS
(global positioning system) to find a receiver (see, for example,
"Introduction to GPS Technology" by Takeyasu Isaka, Tokyo Denki
University Publishing, Feb. 28, 2003). Another known method is AGPS
(assisted GPS), in which positioning is performed by utilizing
assist data indicating a satellite position, etc., acquired from a
mobile unit communication network.
[0006] If finding a position by GPS should fail (that is, if the
GPS positioning result is not fixed), base station positioning, in
which a signal from a mobile unit communication network is used to
perform positioning by pattern matching as mentioned above, or
positioning called hybrid positioning, which combines a signal from
a GPS satellite and a signal from a mobile unit communication
network, is sometimes performed.
[0007] With conventional methods, however, whether or not
positioning by GPS was successful could not be decided without
actually commencing the positioning. Also, GPS positioning that
entailed the above-mentioned decision took a long time. And a
UE-based AGPS positioning method, in which computation is performed
by the receiver, took an especially long time. For example, indoors
where a signal cannot be received from a GPS satellite, after GPS
positioning has proven impossible, the system switched to a
different type of positioning such as base station positioning, so
the overall positioning took a long time. In this case, the
positioning precision is poor for how long the positioning takes.
Also, in cities and the like, even outdoors the effect of
multipulses can prevent good GPS positioning precision from being
attained. Also, the proper positioning time and positioning
precision will vary with how these positioning results are
utilized.
SUMMARY OF THE INVENTION
[0008] The present invention was conceived in light of the above
situation, and it is an object thereof to provide a positioning
system and positioning method with which positioning can be
performed at the proper positioning time and positioning precision
according to a requirement with respect to positioning.
[0009] To achieve the stated object, the positioning system
pertaining to the present invention is a positioning system for
estimating the position of a receiver that has a wireless
communication function and a receiving function for signals used in
GPS positioning, the system comprising first positioning means for
estimating the position of the receiver by a first positioning
method, second positioning means for estimating the position of the
receiver by a second positioning method, requirement information
input means for inputting requirement information indicating a
requirement with respect to estimation of the position of the
receiver, and positioning method determination means for
determining whether to execute the first or second positioning
method on the basis of the requirement information inputted by the
requirement information input means, and causing the first
positioning means or the second positioning means to execute the
estimation of the position of the receiver by the determined
positioning method, wherein the first positioning means comprises
first reception state information acquisition means for acquiring
reception state information indicating the reception state of a
radio wave by the wireless communication function in the receiver,
first position estimation means for estimating the position of the
receiver on the basis of the reception state information acquired
by the first reception state information acquisition means and
performing GPS positioning of the receiver on the basis of the
reception state of a signal used in GPS positioning and received by
the receiver, first end decision means for deciding whether or not
to end the estimation of the position of the receiver by the first
position estimation means on the basis of a specific end condition,
and if it is decided not to end, causing the first position
estimation means to estimate the position of the receiver also on
the basis of new reception state information acquired by the first
reception state information acquisition means at a different timing
from that of the reception state information used to estimate the
position by the first position estimation means, and deciding
whether or not to end the position estimation by the first position
estimation means also on the basis of whether or not GPS
positioning by the first position estimation means has been ended,
first indoor/outdoor determination means for determining whether
the receiver is indoors or outdoors on the basis of the reception
state information acquired by the first reception state information
acquisition means, and first end condition determination means for
determining the specific end condition on the basis of the result
of determination by the first indoor/outdoor determination means,
and the second positioning means comprises second reception state
information acquisition means for acquiring reception state
information indicating the reception state of the radio wave by the
wireless communication function in the receiver, second approximate
position estimation means for estimating an approximate position of
the receiver on the basis of the reception state information
acquired by the second reception state information acquisition
means, and calculating the precision of the approximate position,
second end decision means for deciding whether or not to end the
estimation of the position of the receiver on the basis of the
precision calculated by the second approximate position estimation
means, and if it is decided to end, ending the estimation of the
position of the receiver by using the approximate position
estimated by the second approximate position estimation means as
the position of the receiver, second indoor/outdoor determination
means for determining whether the receiver is indoors or outdoors
on the basis of the reception state information acquired by the
second reception state information acquisition means, and second
positioning control means for controlling the execution of GPS
positioning of the receiver on the basis of the result of decision
by the second end decision means and the result of determination by
the second indoor/outdoor determination means.
[0010] With the positioning system pertaining to the present
invention, requirement information indicating a requirement with
respect to estimation of the position of a receiver is acquired,
and either a first or second positioning method is executed on the
basis of this requirement information. In the first positioning
method, whether the receiver is indoors or outdoors is decided on
the basis of reception state information about the receiver, and an
end condition for the positioning is determined on the basis of
this decision. Therefore, the end condition for positioning can be
selected according to the situation, that is, if it is believed
that the receiver is outdoors and higher positioning precision will
be obtained by taking a relatively long time for positioning, or if
it is believed that the receiver is indoors and higher positioning
precision will not be obtained even if a relatively long time is
taken for positioning. Thus, with the present invention,
positioning can be performed at the proper positioning precision
and in the proper positioning time according to whether the
receiver is indoors or outdoors.
[0011] In the second positioning method, the approximate position
of the receiver is estimated and the precision of the approximate
position is computed on the basis of reception state information
pertaining to the receiver. Whether or not to end the estimation of
the position of the receiver is decided on the basis of the
precision of this approximate position. Therefore, if the precision
of the approximate position is sufficiently good, GPS positioning
is not performed at this point, and the estimation of the position
of the receiver is ended. Meanwhile, whether the receiver is
indoors or outdoors is determined on the basis of reception state
information pertaining to the receiver. The execution of GPS
positioning is controlled on the basis of the decision about
whether or not to end the estimation of the position of the
receiver and the determination about whether the receiver is
indoors or outdoors.
[0012] Therefore, control can be performed so that even if the
receiver does not perform GPS positioning, if the approximate
position has sufficient precision, or if GPS positioning is
difficult to perform, GPS positioning is not executed, and
otherwise GPS positioning is executed. Also, with the above
positioning system, whether or not GPS positioning is performed can
be controlled without actually performing GPS positioning, which
takes a long time to decide if it has been executed. Specifically,
with the positioning system pertaining to the present invention, a
positioning result corresponding to the state of the receiver can
be obtained in less time.
[0013] As discussed above, with the positioning system pertaining
to the present invention, a positioning method corresponding to
requirement information is decided and executed from among two
positioning methods each having a different positioning time and
positioning precision, so positioning can be performed at the
proper positioning time and positioning precision according to a
requirement with respect to positioning.
[0014] Preferably, the first end condition determination means
determines the specific end condition also on the basis of the
requirement information inputted by the requirement information
input means. With this constitution, since a specific end condition
is determined also on the basis of requirement information, the end
condition for positioning can be determined better.
[0015] Preferably, the first end condition determination means
acquires environment information indicating the environment in
which the receiver is placed, and determines the specific end
condition also on the basis of the environment information. With
this constitution, since the end condition is determined also on
the basis of the environment in which the receiver is placed, the
end condition for positioning can be determined better still.
[0016] Preferably, the first reception state information
acquisition means acquires strength information indicating the
reception strength corresponding to an emission source of the radio
wave as the reception state information, and the first position
estimation means estimates the position of the receiver by storing
in advance information indicating the relation between the position
and reception strength of the radio wave corresponding to an
emission source of the radio wave, and by comparing the strength
information acquired by the first reception state information
acquisition means with the information stored in advance. With this
constitution, the position of the receiver can be reliably and
favorably estimated on the basis of the radio wave received by the
wireless communication function of the receiver.
[0017] The first end condition determination means preferably
determines a threshold of positioning result error and/or an
elapsed time of positioning as the specific end condition. With
this constitution, the positioning end condition can be determined
reliably and properly.
[0018] Preferably, the positioning system further comprises
emission source positioning means for acquiring information
indicating the size of a communication area of an emission source
of the radio wave received by the receiver, estimating the position
of the receiver on the basis of the size of the communication area,
and deciding whether or not to cause the first positioning means or
second positioning means to execute the estimation of the position
of the receiver. With this constitution, the positioning result can
be easily acquired according to the environment in which the
receiver is placed.
[0019] Preferably, the second positioning control means controls
the execution of positioning that estimates the position of the
receiver on the basis of the result of decision by the second end
decision means and the result of determination by the second
indoor/outdoor determination means and also on the basis of new
reception state information acquired by the second reception state
information acquisition means, at a timing that differs from that
of the reception state information used to estimate the approximate
position by the second approximate position estimation means. With
this constitution, the positioning result of the receiver can be
obtained even when GPS positioning is not performed.
[0020] Preferably, the reception state information acquisition
means acquires strength information indicating the reception
strength corresponding to an emission source of the radio wave as
the reception state information, and the estimation of the
approximate position by the approximate position estimation means
and the estimation of the position of the receiver which uses the
reception state information and the execution of which is
controlled by the positioning control means, are carried out by a
method in which the position of the receiver is estimated by
storing in advance information indicating the relation between the
position and reception strength of the radio wave corresponding to
the emission source of the radio wave, and by comparing the
strength information acquired by the reception state information
acquisition means with the information stored in advance. With this
constitution, the position of the receiver can be reliably and
favorably estimated on the basis of the radio wave received by the
wireless communication function of the receiver.
[0021] The present invention can be described as an invention of a
positioning system as discussed above, or it can be described as an
invention of a positioning method as follows. Only the categories
here are different, and the invention is substantially the same in
both cases, as are the action and effect.
[0022] Specifically, the positioning method pertaining to the
present invention is a positioning method for estimating the
position of a receiver that has a wireless communication function
and a receiving function for signals used in GPS positioning, the
method comprising a first positioning step of estimating the
position of the receiver by a first positioning method, a second
positioning step of estimating the position of the receiver by a
second positioning method, a requirement information input step of
inputting requirement information indicating a requirement with
respect to estimation of the position of the receiver, and a
positioning method determination step of determining whether to
execute the first or second positioning method on the basis of the
requirement information inputted in the requirement information
input step, and executing the estimation of the position of the
receiver by the determined positioning method in the first
positioning step or the second positioning step, wherein the first
positioning step comprises a first reception state information
acquisition step of acquiring reception state information
indicating the reception state of a radio wave by the wireless
communication function in the receiver, a first position estimation
step of estimating the position of the receiver on the basis of the
reception state information acquired in the first reception state
information acquisition step, and performing GPS positioning of the
receiver on the basis of the reception state of a signal used in
GPS positioning and received by the receiver, a first end decision
step of deciding whether or not to end the estimation of the
position of the receiver in the first position estimation step on
the basis of a specific end condition, and if it is decided not to
end, estimating the position of the receiver in the first position
estimation step also on the basis of new reception state
information acquired in the first reception state information
acquisition step at a different timing from that of the reception
state information used to estimate the position in the first
position estimation step, and deciding whether or not to end the
position estimation in the first position estimation step also on
the basis of whether or not GPS positioning in the first position
estimation step has been ended, a first indoor/outdoor
determination step of determining whether the receiver is indoors
or outdoors on the basis of the reception state information
acquired in the first reception state information acquisition step,
and a first end condition determination step of determining the
specific end condition on the basis of the result of determination
in the first indoor/outdoor determination step, and the second
positioning step comprises a second reception state information
acquisition step of acquiring reception state information
indicating the reception state of the radio wave by the wireless
communication function in the receiver, a second approximate
position estimation step of estimating an approximate position of
the receiver on the basis of the reception state information
acquired in the second reception state information acquisition
step, and calculating the precision of the approximate position, a
second end decision step of deciding whether or not to end the
estimation of the position of the receiver on the basis of the
precision calculated in the second approximate position estimation
step, and if it is decided to end, ending the estimation of the
position of the receiver by using the approximate position
estimated in the second approximate position estimation step as the
position of the receiver, a second indoor/outdoor determination
step of determining whether the receiver is indoors or outdoors on
the basis of the reception state information acquired in the second
reception state information acquisition step, and a second
positioning control step of controlling the execution of GPS
positioning of the receiver on the basis of the result of decision
in the second end decision step and the result of determination in
the second indoor/outdoor determination step.
[0023] With the present invention, since the positioning method
corresponding to requirement information is determined and executed
from among two positioning methods each having a different
positioning time and positioning precision, positioning can be
performed at the proper positioning time and positioning precision
in response to a requirement with respect to positioning.
BRIEF DESCRIPTION OF THE DRAWINGS
[0024] FIG. 1 is a diagram illustrating the functional
configuration of a cellular terminal (receiver) and a positioning
server constituting the positioning system pertaining to an
embodiment of the present invention;
[0025] FIG. 2 is a diagram illustrating the hardware configuration
of a cellular terminal (receiver) pertaining to an embodiment of
the present invention;
[0026] FIG. 3 is a table of information used for determining the
positioning method;
[0027] FIG. 4 is a diagram illustrating the functional
configuration of an indoor/outdoor determination component;
[0028] FIG. 5 is a table illustrating an example of information
stored in a determination database;
[0029] FIG. 6 is a diagram illustrating the hardware configuration
of a positioning server pertaining to an embodiment of the present
invention;
[0030] FIG. 7 is a flowchart of indoor/outdoor determination
processing (indoor/outdoor determination method);
[0031] FIG. 8 is a diagram illustrating the processing in FIG.
7;
[0032] FIG. 9 is a diagram illustrating the construction of a
determination database;
[0033] FIG. 10 is a flowchart illustrating the processing
(positioning method) executed by a cellular terminal (receiver) and
a positioning server constituting the positioning system pertaining
to an embodiment of the present invention;
[0034] FIG. 11 is a flowchart illustrating positioning processing
by a hybrid algorithm 1;
[0035] FIG. 12 is a flowchart illustrating positioning processing
by the hybrid algorithm 1;
[0036] FIG. 13 is a flowchart illustrating positioning processing
by a hybrid algorithm 2;
[0037] FIG. 14 is a flowchart illustrating a first modification
example of an indoor/outdoor determination processing
(indoor/outdoor determination method);
[0038] FIG. 15 is a diagram illustrating the functional
configuration of a second modification example of an indoor/outdoor
determination component; and
[0039] FIG. 16 is a flowchart illustrating a second modification
example of an indoor/outdoor determination processing
(indoor/outdoor determination method).
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0040] Preferred embodiments of the positioning system and
positioning method pertaining to the present invention will now be
described in detail along with the drawings. Those elements that
are the same in the drawings will be numbered the same, and
redundant description will be omitted.
[0041] FIG. 1 shows a positioning system 1 pertaining to this
embodiment. A positioning system 1 is a system for estimating the
position of a cellular terminal (mobile communication terminal) 20
that is the receiver pertaining to this embodiment, and comprises a
positioning server 10 and the cellular terminal 20. The positioning
server 10 is a device for estimating the position of the cellular
terminal 20 (performing comprehensive processing). The (control of
the) positioning of the cellular terminal 20 by the positioning
server 10 is performed by using only the framework of a cellular
communication system (mobile communication system). The positioning
server 10 is connected with a plurality of cellular base stations
30 included in the cellular communication system, and can send and
receive information to and from each of the cellular base stations
30. Communication with the cellular terminal 20 can also be
performed via the cellular base stations 30. The positioning server
10 may also be included in a cellular communication system (mobile
communication system).
[0042] The cellular terminal 20 that is the object of positioning
will be described before the positioning server 10 pertaining to
this embodiment is described in detail. The cellular terminal 20 is
a device that has a wireless communication function and a receiving
function for signals used in GPS positioning (AGPS positioning).
The cellular terminal 20 also has a function that performs GPS
positioning computation. More specifically, the cellular terminal
20 comprises a cellular communication component 21, a GPS reception
component 22, a GPS positioning computer 23, and a data storage
component 24, as shown in FIG. 1.
[0043] The cellular communication component 21 is a means for
performing cellular communication (mobile unit communication) by
wireless communication between the plurality of cellular base
stations 30 included in the cellular communication network (mobile
unit communication network) of the cellular communication system.
The cellular communication component 21 is provided with an antenna
for cellular communication, and this antenna is used to perform
cellular communication. The cellular communication component 21
performs ordinary cellular communication such as telephone
communication, and also acquires information by cellular
communication used for positioning of its own terminal 20 in the
positioning server 10. How this information is acquired will be
discussed in more specific terms below. The cellular communication
component 21 stores the acquired information in the data storage
component 24.
[0044] Also, the cellular communication component 21 sends and
receives information to and from the positioning server 10 via the
cellular base stations 30 (cellular communication network). The
cellular communication component 21 sends the positioning server 10
information that is stored in the data storage component 24 and
used by the positioning server 10 for positioning, and more
specifically, the measurement report information (discussed below).
Information sent from the cellular communication component 21 to
the positioning server 10 includes information indicating the GPS
positioning result (discussed below), information related to
wireless communication (discussed below), or information for
producing information related to wireless communication. This
transmission is triggered by user operation of the terminal 20 or
by a request from the positioning server 10, for example, when the
cellular terminal 20 is being positioned.
[0045] The GPS reception component 22 is a means for receiving a
signal that is sent from a GPS satellite 40 and used for
positioning. The GPS reception component 22 is provided with an
antenna for receiving signals from a GPS satellite, and this
antenna is used to perform reception. The GPS reception component
22 stores information related to the signals received from GPS
satellites 40 and used in GPS positioning computation, in the data
storage component 24.
[0046] The GPS satellites 40 are located at specific places
corresponding to the time of day, and send positioning signals from
this location. More specifically, four or five of the GPS
satellites 40 are disposed in six orbits at an altitude of
approximate position 20,000 Km, and move along their orbits as time
passes. The positioning signals sent by the GPS satellites 40
include identification information for identifying a specific GPS
satellite 40, information indicating the orbit of the GPS
satellites 40, and information indicating the time a signal was
sent.
[0047] The GPS positioning computer 23 is one of first and second
position estimation means for calculating by GPS positioning the
position of the terminal 20 on the basis of the reception state of
a signal from a GPS satellite 40 received by the GPS reception
component 22. More specifically, the GPS positioning computer 23
acquires information about a signal received by the terminal 20
from a GPS satellite 40, which is received by the GPS reception
component 22 and stored in the data storage component 24. Then, the
GPS positioning computer 23 computes from this information the
location of the GPS satellite 40, the distance form the cellular
terminal 20 to the GPS satellite 40, and so forth, and computes the
location of the terminal 20. For this computation, assist data
acquired from the cellular communication system and indicating the
location of the GPS satellite 40, etc., may be used (in which case
the positioning will be AGPS (assisted GPS)). The starting and
ending of the reception of signals from the GPS satellite 40 by the
GPS reception component 22 and the GPS positioning computation by
the GPS positioning computer 23 are triggered, for example, by the
receipt of an instruction from the positioning server 10 by the
cellular terminal 20, which will be discussed below.
[0048] The GPS positioning computer 23 sends information indicating
the computed location of the terminal 20 to the positioning server
10 as information about the positioning result of GPS positioning.
If computation of the location of the terminal 20 by GPS
positioning should fail, the GPS positioning computer 23 sends the
positioning server 10 a notification to this effect. This
information is included in the measurement report information that
is sent.
[0049] The data storage component 24 holds information used for
positioning and acquired by the cellular communication component 21
and the GPS reception component 22. The above is the functional
configuration of the cellular terminal 20.
[0050] Information about the position of a cellular terminal 20
estimated by a positioning system 1 is utilized by applications
(software) executed by the cellular terminal 20 or by a server or
the like that provides information to the cellular terminal 20.
More specifically, the estimated position of the cellular terminal
20 is used for navigation, providing information corresponding to
the position of the user, or the like. These applications have
different requirements pertaining to the applications themselves
and to estimating the position of the cellular terminal 20
according to application settings and so forth. Examples of such
requirements include reducing the battery consumption of the
cellular terminal 20 (so as to allow continuous positioning over a
longer time), and improving positioning precision. In this
embodiment, when the positioning system 1 performs positioning of
the cellular terminal 20, information indicating a requirement
pertaining to positioning is acquired by a positioning server 10,
such as receiving information transmitted from a positioning
requirement source (such as the cellular terminal 20).
[0051] FIG. 2 illustrates the hardware configuration of a cellular
terminal 20 pertaining to this embodiment. As shown in FIG. 2, the
cellular terminal 20 is made up of a CPU (central processing unit)
201, a RAM (random access memory) 202, a ROM (read only memory)
203, a control unit 204, a display 205, a cellular communication
module 206, a cellular communication antenna 207, a GPS reception
module 208, a GPS reception antenna 209, and other such hardware.
The functions mentioned above are exhibited when these constituent
elements operate. The above is the constitution of the cellular
terminal 20.
[0052] The positioning server 10 will now be described. As shown in
FIG. 1, the positioning server 10 comprises a transceiver 11, a
first positioning component 12, a second positioning component 13,
a requirement information input component 14, a positioning method
determination component 15, and a cell ID positioning component
16.
[0053] The transceiver 11 is a means for sending and receiving
information to and from the cellular terminal 20 via a cellular
base station 30. The transceiver 11 outputs information received
from the cellular terminal 20 to the first positioning component
12, the second positioning component 13, the requirement
information input component 14, or the cell ID positioning
component 16 according what the information is.
[0054] The first positioning component 12 is a first positioning
means for estimating the position of the cellular terminal 20 with
a hybrid algorithm 1 that is a first positioning method. The second
positioning component 13 is a second positioning means for
estimating the position of the cellular terminal 20 with a hybrid
algorithm 2 that is a second positioning method. The hybrid
algorithms 1 and 2 will be described in further detail below, but
each has the following characteristics.
[0055] The hybrid algorithm 1 optimizes the positioning time and
positioning precision, but since GPS positioning and pattern
matching positioning are executed simultaneously, the power
consumption of the cellular terminal 20 (battery consumption) is
greater. The hybrid algorithm 2 executes GPS positioning and
pattern matching positioning alternately, so positioning time and
positioning precision cannot be optimized, but the power
consumption of the cellular terminal 20 is lower. Also, as will be
discussed in further detail below, since an approximate position is
also utilized, the positioning time is shorter. As mentioned above,
the hybrid algorithms 1 and 2 have different characteristics in
terms of their positioning time and positioning precision and the
power consumption of the cellular terminal 20.
[0056] The requirement information input component 14 is a
requirement information input means for inputting requirement
information indicating a requirement with respect to estimation of
the position of the cellular terminal 20. More specifically, this
requirement pertains to the positioning time, the positioning
precision, the battery life of the cellular terminal 20, and so
forth. More specifically, examples include best battery life (so
that the battery life of the cellular terminal 20 is as long as
possible), best time-to-fix (so that the positioning time is as
short as possible), and best positioning precision (so that the
positioning precision is as high as possible). Other examples
include better battery life, better time-to-fix, better precision,
good battery life, good time-to-fix, good precision, and other such
requirements including the priority of elements.
[0057] More specifically, the requirement information input
component 14 inputs requirement information by receiving
information transmitted from a positioning requirement source (such
as the cellular terminal 20). The above-mentioned requirement is
usually determined on the basis of an application setting or the
application itself in which the positioning result is used. The
requirement information input component 14 outputs the inputted
requirement information to the positioning method determination
component 15.
[0058] The positioning method determination component 15 is a
positioning method determination means for determining whether to
execute the hybrid algorithm 1 or the hybrid algorithm 2 on the
basis of the requirement information inputted from the requirement
information input component 14. More specifically, the positioning
method determination component 15 determines the positioning method
on the basis of information in the table shown in FIG. 3, which is
stored ahead of time in the positioning server 10. The information
in the table shown in FIG. 3 is information that is associated with
requirement information (information in the first column of the
table) and the positioning method (information in the third column
of the table) (information other than the information in the table
shown in FIG. 3 will be discussed below). In FIG. 3, the "HA1" and
"HA2" listed as positioning methods indicate hybrid algorithm 1 and
hybrid algorithm 2, respectively.
[0059] The positioning method determination component 15 refers to
the table in FIG. 3 and determines the positioning method
associated with the requirement information inputted from the
requirement information input component 14 to be the positioning
method that will be executed. The positioning method determination
component 15 causes the first positioning component 12 or the
second positioning component 13 to execute the estimation of the
position of the cellular terminal 20 by the determined positioning
method. If positioning is executed by the first positioning
component 12, then the positioning method determination component
15 inputs to the first positioning component 12 the requirement
information used for determining the positioning end condition.
[0060] The cell ID positioning component 16 is an emission source
positioning means for acquiring information indicating the size of
a communication area of the cellular base station 30, which is an
emission source of radio waves received by the cellular terminal
20, and estimates the position of the receiver on the basis of the
size of the communication area. The cell ID positioning component
16 decides whether or not to cause the first positioning system 12
or second positioning component 13 to execute the estimation of the
position of the cellular terminal 20 on the basis of information
indicating the size of the communication area.
[0061] More specifically, the cell ID positioning component 16
performs estimation of the position of the cellular terminal 20 as
follows. The cell ID positioning component 16 acquires, via the
transceiver 11, the cell ID of the cellular base station 30 that is
the emission source of the radio wave received by the cellular
terminal 20. The cell ID may be acquired from MR just as above, or,
in this case, since there is no need for reception strength
information, etc., it may be sent separately from the cellular
terminal 20. The cell ID used here pertains to a single cell, and
if the MR includes information about a plurality of cells, then
information about the cell with the highest reception strength
above a specific reception strength is used.
[0062] Then the cell ID positioning component 16 estimates the
radius R of the cell (the size of the cell), which is the
communication area of the cellular base station 30 pertaining to
the cell ID. The estimation of the cell radius R is performed in
the same way as in a conventional method. For instance, a cell
radius database storing information indicating the cell radius
corresponding to the cell ID is held in advance in the cell ID
positioning component 16, and the cell radius R is estimated on the
basis of this. Alternatively, information indicating the positional
relation of the cell is stored in advance, and information for the
adjacent cell is used to estimate the cell radius R.
[0063] The cell ID positioning component 16 compares the estimated
cell radius R with a threshold dr that was stored in advance. If
the cell ID positioning component 16 decides that the estimated
cell radius is below the threshold dr, it can be estimated that the
cellular terminal 20 is located at the position of that cell (the
position of the cellular base station 30), and that cell ID is used
as the positioning result. The threshold dr is suitably set
according to the required precision of positioning with respect to
the cellular terminal 20. Usually, if the required precision is
relatively low, the threshold dr is set relatively large. If the
cell ID positioning component 16 decides that the estimated cell
radius is not below the threshold dr, then the positioning result
is that the position cannot be estimated by cell ID.
[0064] As discussed below, the estimation of the position of the
cellular terminal 20 using a cell ID is performed as the first
processing in the estimation processing for the position of the
cellular terminal 20. This is because if the position of the
cellular terminal 20 can estimated with such simple computation and
information, then pattern matching position computation and GPS
positioning computation need not be performed.
[0065] If the cell ID positioning component 16 can estimate the
position of the cellular terminal 20 by cell ID, then the estimated
position is used as the final positioning result, and it is decided
to end estimation of the position of the cellular terminal 20.
Specifically, the cell ID positioning component 16 decides whether
or not to end the estimation of the position on the basis of the
cell radius. If the cell ID positioning component 16 is not
successful at estimating the position of the cellular terminal 20
by cell ID, then it is decided not to end estimation of the
position of the cellular terminal 20, and it is decided to have the
first positioning component 12 or the second positioning component
13 execute estimation of the position of the cellular terminal
20.
[0066] If the cell ID positioning component 16 decides to end the
estimation of the position of the cellular terminal 20, it sends a
signal that halts the processing for positioning with respect to
the cellular terminal 20 via the transceiver 11, in the same manner
as described later. Alternatively, since the estimation of the
position of the cellular terminal 20 using cell ID is performed as
the first processing in the estimation processing for the position
of the cellular terminal 20, if the cell ID positioning component
16 decides not to end the estimation of the position of the
cellular terminal 20, it may send a signal that begins processing
for GPS positioning and pattern matching positioning with respect
to the cellular terminal 20 via the transceiver 11. In that case,
the elapsed time of positioning described later is counted from
that point.
[0067] The first positioning component 12 that executes a hybrid
algorithm 1 will now be described in detail. As shown in FIG. 1,
the first positioning component 12 comprises a first reception
state information acquisition component 121, a first base station
positioning computer 122, a first end decision component 123, a
first indoor/outdoor determination component 124, and a first end
condition determination component 125.
[0068] The first reception state information acquisition component
121 is first reception state information acquisition means for
acquiring, via the transceiver 11, reception state information sent
from the cellular terminal 20 and indicating the reception state of
a radio wave produced by the cellular communication component 21 at
the cellular terminal 20. Strength information indicating the
reception strength corresponding to the cellular base station 30
that is the emission source of the radio wave is used as the
reception state information. More specifically, measurement report
information (hereinafter abbreviated as MR) including
identification information for the cellular base stations 30 (cell
ID, base station ID, etc.), which is information measured at the
cellular terminal 20, is used. In addition to identification
information for the cellular base stations 30, the MR includes
information indicating the signal transmission lag (such as the RTT
(round trip time)) and the reception strength (reception level) of
the received signal associated with the pertinent identification
information, information indicating the amount of attenuation, the
amount of interference, etc., whether or not GPS positioning is
possible, and so forth. Upon acquiring the MR, the first reception
state information acquisition component 121 outputs the MR to the
first base station positioning calculator 122 and the
indoor/outdoor determination component 124. The acquisition of MR
is carried out intermittently, such as at regular time
intervals.
[0069] The first base station positioning calculator 122 is one of
first position estimation means for estimating the position of the
cellular terminal 20 on the basis of the MR acquired by the first
reception state information acquisition component 121. The
estimation of the position of the cellular terminal 20 based on MR
is performed by the method given in the above-mentioned Japanese
Patent Application No. H7-231473, which involves positioning
calculation by pattern matching. Specifically, the first base
station positioning calculator 122 stores, in a database or the
like, information indicating the relation between the reception
strength of the radio wave received from a specific cellular base
station 30 and the location where this radio wave is received. The
first base station positioning calculator 122 matches the
information stored in this database with the reception strength
corresponding to the cellular base station 30 indicated by the MR,
and the location associated with the reception strength of a
pattern similar to the reception strength indicated by the MR is
termed the location of the cellular terminal 20.
[0070] The first base station positioning calculator 122 estimates
the location of the cellular terminal 20 as discussed above, and
also estimates the positioning error of this location. The
estimation of positioning error here is carried out in the same
manner as the estimation of positioning error by a conventional
positioning method that involves pattern matching. The first base
station positioning calculator 122 computes, for example, the
degree of match Pi between the reception strength of the MR and the
reception strength associated with each location stored in the
database. Then, the first base station positioning calculator 122
computes the positioning error Ei using the following function, for
example, in which Pi is a variable.
Ei=A/Pi
[0071] Here, A is a system parameter stored in advance by the first
base station positioning calculator 122. As an example of how Pi is
computed, it is possible to use the Euclid distance between a
measurement result M and a database D. We will let i be a number
that uniquely identifies a position coordinate in the database, and
let j be a base station number received by measurement, and Pi is
calculated by the following formula for all the position
coordinates i in the database.
Pi = 1 J ( M j - D i , j ) 2 ##EQU00001##
[0072] The position where Pi is greatest is the position with the
best match. It is also possible to use the size of the grid in the
database for A. That is, the distance between adjacent positions in
the database is used as A.
[0073] The first base station positioning calculator 122 uses a
plurality of MR to perform positioning calculation when a plurality
of MR are acquired in positioning of the cellular terminal 20 one
time. More specifically, the first base station positioning
calculator 122 averages the reception strength of the radio wave
indicated by a plurality of MR for each of the cellular base
stations 30, and uses the averaged reception strength to perform
matching. In pattern matching positioning, measurement is repeated
at the cellular terminal 20, and increasing the number of MR has
the effect of eliminating fluctuation in the measurement result
caused by measurement error or multipulses, so positioning
precision is improved. As discussed below, the MR is sent to the
positioning server 10 every time MR is measured at the cellular
terminal 20, so the first base station positioning calculator 122
performs pattern matching positioning calculation every time this
happens. The first base station positioning calculator 122 outputs
to the first end decision component 123 information indicating the
location of the cellular terminal 20 obtained by pattern matching
positioning calculation, and information indicating the calculated
positioning error.
[0074] The first end decision component 123 is first end decision
means for deciding whether or not to end the estimation of the
position of the cellular terminal 20 on the basis of a specific end
condition. More specifically, every time pattern matching
positioning computation is performed, the first end decision
component 123 decides the end of pattern matching positioning and
GPS positioning as follows. First, the first end decision component
123 decides whether or not GPS positioning has ended. A positioning
result for GPS positioning is sent from the cellular terminal 20 to
the positioning server 10, and it is decided whether or not this
has been received by the transceiver 11 and inputted to the first
end decision component 123. If the GPS positioning result has been
inputted to the first end decision component 123, then the first
end decision component 123 decides that GPS positioning has ended.
If it has been decided that GPS positioning has ended, it is
decided to end the estimation of the position of the cellular
terminal 20. In this case, the first end decision component 123
uses the positioning result for GPS positioning as the position of
the cellular terminal 20.
[0075] Moreover, the end decision component 123 decides whether or
not to end the estimation of the position of the cellular terminal
20 by deciding whether or not the positioning error of the
positioning result obtained by pattern matching positioning
computation by the base station positioning calculator 122 is below
a threshold .sigma..sub.T as the specific end condition. If the end
decision component 123 decides that the positioning error is less
than that threshold .sigma..sub.T, it decides to end the estimation
of the position of the cellular terminal 20. This means that
positioning is ended when the positioning result obtained by
pattern matching positioning computation by the base station
positioning calculator 122 satisfies a specific positioning
precision. The threshold .sigma..sub.T is determined by the end
condition determination component 125 as described below. In this
case, the end decision component 123 uses the positioning result
from pattern matching positioning as the position of the cellular
terminal 20.
[0076] The end decision component 123 also decides whether or not
to end the estimation of the position of the cellular terminal 20
by deciding whether or not the positioning elapsed time is greater
than a threshold T as the specific end condition. If the end
decision component 123 decides that the positioning elapsed time is
greater than the threshold T, it decides to end the estimation of
the position of the cellular terminal 20. The positioning elapsed
time is measured by the positioning server 10, and is the elapsed
time from the start of positioning with respect to the cellular
terminal 20. The threshold T is determined by the end condition
determination component 125 as described below. In this case, the
end decision component 123 uses the positioning result for pattern
matching positioning as the position of the cellular terminal
20.
[0077] As discussed above, if the end decision component 123
decides to end the estimation of the position of the cellular
terminal 20, it sends a signal that halts positioning processing to
the cellular terminal 20 via the transceiver 11. Specifically, it
sends a signal that halts the reception of signals from the GPS
satellite 40, GPS positioning computation, and the measurement of
MR. Also, the end decision component 123 outputs information
indicating the position of the cellular terminal 20 estimated as
above, corresponding to the usage details, such as sending it to
the cellular terminal 20.
[0078] In the above-mentioned decision, if it is decided not to end
the estimation of the position of the cellular terminal 20 (if it
is not decided to end it), the first end decision component 123
instructs the first base station positioning calculator 122 to
perform pattern matching positioning computation on the basis of
new MR acquired at a different timing from that of the MR used in
the pattern matching positioning performed by the first base
station positioning calculator 122. Specifically, when new MR is
acquired by the first reception state information acquisition
component 121, the first base station positioning calculator 122 is
instructed to use that MR as well to perform pattern matching
positioning computation of the cellular terminal 20. However,
active control of the first base station positioning calculator 122
from the first end decision component 123 does not necessarily have
to be performed, and the system may be such that pattern matching
positioning computation is performed by not performing positioning
end processing as above.
[0079] The indoor/outdoor determination component 124 is an
indoor/outdoor determination means for determining whether the
cellular terminal 20 is indoors or outdoors on the basis of the MR
inputted from the first reception state information acquisition
component 121. As shown in FIG. 4, the indoor/outdoor determination
component 124 more specifically comprises a determination database
51, a reception component 52, a specification component 53, a
possibility determination component 54, a first indoor/outdoor
determination component 55, and a second indoor/outdoor
determination component 56.
[0080] As shown in FIG. 5, the determination database 51 stores
combined information for identification information about an
outdoor emission source that is assumed to be the emission source
(cellular base station 30) of the signals received simultaneously
by the cellular terminal 20, and indoor/outdoor characteristic
information expressing the indoor or outdoor characteristics of the
cellular terminal 20 at the time of signal receipt (as an example
here, this is information expressing whether or not GPS positioning
is possible (hereinafter referred to as GPS possibility
information)), with these groups of information associated. FIG. 5
shows, for example, results from when signals are received
simultaneously from emission sources BTS-A, BTS-B, and BTS-D, in
which case it is indicated that GPS positioning is possible, and
results from when signals are received simultaneously from emission
sources BTS-A, BTS-B, and BTS-E, in which case it is indicated that
GPS positioning is not possible. The configuration of the
determination database 51 will be discussed below.
[0081] The reception component 52 receives from the cellular
terminal 20 MR that includes information identifying the emission
source of the received signal. The specification component 53
specifies the number N of emission sources of received signals from
the received MR. The possibility determination component 54
determines whether or not the emission source number N is equal to
or greater than the minimum emission source number M at which
indoor/outdoor determination is possible on the basis of a first
indoor/outdoor determination method (discussed below). The minimum
emission source number M is a preset value.
[0082] The first indoor/outdoor determination component 55 executes
indoor/outdoor determination on the basis of the first
indoor/outdoor determination method when the emission source number
N is equal to or greater than the minimum emission source number M
(that is, when indoor/outdoor determination is possible on the
basis of the first indoor/outdoor determination method). An example
of the indoor/outdoor determination based on the first
indoor/outdoor determination method here is to calculate the
approximate position of the cellular terminal 20 by referring to a
positioning database in which MR from the cellular terminal 20 has
been stored in advance, and determine indoors or outdoors on the
basis of whether or not there is a contradiction between the
measurement data in the MR and the predicted data in the
approximate position.
[0083] The second indoor/outdoor determination component 56
executes indoor/outdoor determination on the basis of a second
indoor/outdoor determination method (discussed below) when the
emission source number N is less than the minimum emission source
number M (that is, when indoor/outdoor determination is impossible
on the basis of the first indoor/outdoor determination method).
[0084] The indoor/outdoor determination component 124 outputs the
result of determining whether the cellular terminal 20 is indoors
or outdoors to the first end condition determination component 125
shown in FIG. 1.
[0085] The first end condition determination component 125 is first
end condition determination means for determining the specific end
condition used in the decision by the first end decision component
123 on the basis of the result of determination by the
indoor/outdoor determination means 124. The first end condition
determination component 125 determines a threshold .sigma..sub.T
for positioning error of the above-mentioned pattern matching, and
a threshold T for the elapsed time of the positioning. If the
result of determination by the indoor/outdoor determination
component 124 is that the cellular terminal 20 is located indoors,
the first end condition determination component 125 sets the
threshold .sigma..sub.T (relatively) high and the threshold T
(relatively) low. On the other hand, if the result of determination
by the indoor/outdoor determination component 124 is that the
cellular terminal 20 is located outdoors, the first end condition
determination component 125 sets the threshold .sigma..sub.T
(relatively) low and the threshold T (relatively) high. This is
because when the cellular terminal 20 is located outdoors, higher
positioning precision will be obtained by taking a relatively long
time for positioning, and if the cellular terminal 20 is located
indoors, higher positioning precision will not be obtained even if
a relatively long time is taken for positioning.
[0086] Also, as the result of determination by the indoor/outdoor
determination component 124, for example, a value d.sub.i that is
continuous between 0 and 1 is outputted as the extent to which the
cellular terminal 20 is indoors, the threshold .sigma..sub.T and
the threshold T may be determined by the following formulas. Here,
d.sub.i=0 means outdoors, and d.sub.i=1 means indoors.
.sigma..sub.T=d.sub.i(.sigma..sub.PM-.sigma..sub.AGPS)+.sigma..sub.AGPS
T=d.sub.i(T.sub.0-T.sub.i)+T.sub.i
[0087] Here, .sigma..sub.AGPS and .sigma..sub.PM express the
thresholds of positioning error for AGPS positioning and pattern
matching positioning, respectively. T.sub.i and T.sub.0 express the
control times indoors and outdoors, respectively. These values may
be system parameters stored by the first end condition
determination component 125 ahead of time. These values may also be
calculated each time by individual functions using the estimated
cell radius R. For example, .sigma..sub.AGPS and T.sub.0 are
strictly increasing functions of R, and .sigma..sub.PM and T.sub.i
are strictly decreasing functions of R. The first end condition
determination component 125 outputs information indicating the
determined end condition to the first end decision component
123.
[0088] The first end condition determination component 125 may also
decide a specific end condition on the basis of requirement
information inputted by the requirement information input component
14. Furthermore, the first end condition determination component
125 may acquire environment information indicating the environment
in which the cellular terminal 20 is placed, and decide a specific
end condition on the basis of the environment information. Examples
of the environment in which the cellular terminal 20 is placed
include those in which the cellular terminal 20 setting is urban,
suburban, or rural.
[0089] The acquisition of environment information is performed, for
example, by making a determination on the basis of a positioning
database stored in the first base station positioning computer 122
from MR data transmitted from the cellular terminal 20. More
specifically, the cellular terminal 20 acquires information
indicating the cell distance from the cellular base station 30 (to
the adjacent cellular base station 30) that has received radio
waves, and determines the environment on the basis of this cell
distance. For instance, the setting is determined to be urban if
the cell distance is below a specific threshold. The environment
information may be acquired from the cellular terminal 20, in
addition to being acquired by determination as above.
[0090] In specific terms, the determination of the end condition is
performed on the basis of the information in the table shown in
FIG. 3 and stored ahead of time in the positioning server 10. The
information in the table shown in FIG. 3 is information in which
requirement information (the information in the first column of the
table) and environment information (the information in the second
column of the table) are associated with information indicating the
end condition (the information in the fourth to seventh columns of
the table).
[0091] Of the information indicating the end condition shown in the
table of FIG. 3, .sigma..sub.T.sub.--.sub.in (the information in
the fourth column of the table) is the threshold .sigma..sub.T (in
units of meters) of pattern matching positioning error when the
cellular terminal 20 was located indoors.
.sigma..sub.T.sub.--.sub.out (the information in the fifth column
of the table) is the threshold .sigma..sub.T (in units of meters)
of pattern matching positioning error when the cellular terminal 20
was located outdoors. T.sub.max.sub.--.sub.in (the information in
the sixth column of the table) is the threshold T (in units of
seconds) of elapsed positioning time when the cellular terminal 20
was located indoors. T.sub.max.sub.--.sub.out (the information in
the seventh column of the table) is the threshold T (in units of
seconds) of elapsed positioning time when the cellular terminal 20
was located outdoors. "A-GPS Timeout time" in FIG. 3 is the timeout
time of AGPS positioning preset and stored in the positioning
server 10. "Time to Acquire First NMR" is the time until the first
MR data is acquired.
[0092] The first end condition determination component 125 refers
to the table in FIG. 3 and uses an end condition associated with a
combination of the acquired environment information and the
requirement information inputted by the requirement information
input component 14. When the table of FIG. 3 is used, the end
condition is determined by a combination of requirement information
and environment information, but the end condition may instead be
determined by either the requirement information or the environment
information. If the end condition is determined as discussed above,
then since the end condition is determined on the basis of
requirement information and environment information in addition to
indoor/outdoor determination, the proper end condition for
positioning is determined. The above is the constitution of the
first positioning component 12.
[0093] Next, the second positioning component 13 that executes the
hybrid algorithm 2 will be described in detail. As shown in FIG. 1,
the second positioning component 13 comprises a second reception
state information acquisition component 131, a second base station
positioning computer 132, a second end decision component 133, a
second indoor/outdoor determination component 134, and a second end
condition determination component 135.
[0094] The second reception state information acquisition component
131 acquires, via the transceiver 11, reception state information
indicating the reception state of radio waves by a cellular
communication component 21 in the cellular terminal 20. The second
reception state information acquisition component 131 has the same
function as the first reception state information acquisition
component 121 of the first positioning component 12. When MR data
is acquired, the second reception state information acquisition
component 131 outputs this MR data to the second base station
positioning computer 132 and the second indoor/outdoor
determination component 134. The acquisition of MR data is carried
out continually, such as at regular intervals.
[0095] The second base station positioning computer 132 is one
second position estimation means for estimating the position of the
cellular terminal 20 on the basis of MR data acquired by the second
reception state information acquisition component 131. The second
base station positioning computer 132 performs pattern matching
positioning computation by the same function as the first base
station positioning computer 122 of the first positioning component
12. The second base station positioning computer 132 outputs
information indicating the position of the cellular terminal 20
obtained by pattern matching positioning computation, and
information indicating the calculated positioning error to the
second end decision component 133.
[0096] The second base station positioning calculator 132 is second
approximate position estimation means for estimating the
approximate position of the cellular terminal 20 and also computing
the precision of this approximate position by the above-mentioned
pattern matching positioning method from the MR initially acquired
in positioning of the cellular terminal 20. The above-mentioned
positioning error is used as the precision of the approximate
position. The second base station positioning calculator 132
outputs information about the approximate position found as above
to the second end decision component 133. The calculation of the
approximate position does not necessarily have to be based on a
single MR, and may instead be based on MR from a number of times.
Since the approximate position is found in a short time along with
the determination of indoors or outdoors as discussed below, it may
be found on the basis of the same information as that used for the
determination of indoors or outdoors.
[0097] The second end decision component 133 is second end decision
means for deciding whether or not to end the estimation of the
position of the cellular terminal 20 on the basis of specific end
conditions. More specifically, the second end decision component
133 decides whether or not to end the estimation of the position of
the cellular terminal 20 on the basis of the precision of the
approximate position of the cellular terminal 20 estimated by the
second base station positioning calculator 132. The second end
decision component 133 makes its decision based on the precision of
the approximate position by deciding whether or not the positioning
error of the approximate position indicated by the information
inputted from the second base station positioning calculator 132 is
less than a threshold. If the second end decision component 133
decides that the positioning error is below the threshold, it
decides that the precision of the approximate position is adequate,
and ends the estimation of the position of the cellular terminal
20. The above-mentioned threshold is a value stored in advance in
the second end decision component 133, and is suitably set
according to the required precision of the cellular terminal 20. In
this case, the second end decision component 133 terms the
approximate position to be the position of the cellular terminal
20.
[0098] As discussed above, if the second end decision component 133
decides to end the estimation of the position of the cellular
terminal 20, it sends a signal that halts positioning processing to
the cellular terminal 20 via the transceiver 11. Specifically, it
sends a signal that halts the reception of signals from the GPS
satellite 40, the GPS positioning computation, and the measurement
of MR. There may be an instruction to commence processing
pertaining to GPS positioning when the positioning server 10
decides that GPS positioning is to be performed, as discussed
below. Also, the second end decision component 133 outputs
information indicating the position of the cellular terminal 20
estimated as above, corresponding to the usage details, such as
sending it to the cellular terminal 20.
[0099] If the second end decision component 133 decides that the
positioning error is not below the threshold, it decides that the
precision of the approximate position is insufficient, and does not
end the estimation of the position of the cellular terminal 20. In
the above-mentioned decision, if it is decided not to end the
estimation of the position of the cellular terminal 20 (if it is
not decided to end it), either pattern matching positioning or GPS
positioning is carried out as discussed below. In that case, the
second end decision component 133 decides to end the positioning as
discussed below. Also, the second end decision component 133
outputs to the second positioning controller 135 information about
the result of deciding whether or not to end positioning processing
on the basis of the approximate position.
[0100] When GPS positioning is performed, more specifically, the
second end decision component 133 decides to end the estimation of
the position of the cellular terminal 20 upon receiving
notification of the GPS positioning result from the cellular
terminal 20. If the notification from the cellular terminal 20 is
to the effect that the GPS positioning succeeded and a positioning
result has been obtained by GPS positioning (if the GPS positioning
is fixed), the second end decision component 133 uses the
above-mentioned approximate position as the position of the
cellular terminal 20. On the other hand, if the notification from
the cellular terminal 20 is to the effect that GPS positioning
failed and a positioning result has not been obtained by GPS
positioning (if GPS positioning is not fixed), the second end
decision component 133 uses the above-mentioned approximate
position as the position of the cellular terminal 20. Also, if
there is no notification from the cellular terminal 20 even after a
specific length of time has elapsed (such as a preset specific
time), the second end decision component 133 uses the
above-mentioned approximate position as the position of the
cellular terminal 20. Also, the second end decision component 133
outputs information indicating the position of the cellular
terminal 20 estimated as above, corresponding to the usage details,
such as sending it to the cellular terminal 20.
[0101] When pattern matching positioning is performed, or more
specifically, when pattern matching is performed on the basis of
new MR and the positioning result is inputted from the second base
station positioning calculator 132 to the second end decision
component 133, the second end decision component 133 decides to end
the estimation of the position of the cellular terminal 20. In that
case, the positioning error in pattern matching positioning does
not necessarily have to be calculated. Alternatively, the second
end decision component 133 may make a decision as follows. Every
time pattern matching positioning computation is performed by the
second base station positioning calculator 132, the second end
decision component 133 decides as follows to end the pattern
matching positioning. The second end decision component 133 decides
whether or not to end the estimation of the position of the
cellular terminal 20 by deciding whether or not the positioning
error of the positioning result obtained by pattern matching
positioning computation by the second base station positioning
calculator 132 is below a threshold .sigma..sub.T. If the second
end decision component 133 decides that the positioning error is
less than that threshold .sigma..sub.T, it decides to end the
estimation of the position of the cellular terminal 20. This means
that positioning is ended when the positioning result obtained by
pattern matching positioning computation by the second base station
positioning calculator 132 satisfies a specific positioning
precision. The threshold .sigma..sub.T is a value that is stored in
the second end decision component 133 in advance, and is suitably
set according to the required precision of the cellular terminal
20. In this case, the second end decision component 133 uses the
positioning result from pattern matching positioning as the
position of the cellular terminal 20.
[0102] The second end decision component 133 also decides whether
or not to end the estimation of the position of the cellular
terminal 20 by deciding whether or not the positioning elapsed time
is greater than a threshold T. If the second end decision component
133 decides that the positioning elapsed time is greater than the
threshold T, it decides to end the estimation of the position of
the cellular terminal 20. The positioning elapsed time is measured
by the positioning server 10, and is the elapsed time from the
start of positioning with respect to the cellular terminal 20. The
threshold T is a value that is stored in the second end decision
component 133 in advance, and is suitably set according to the
allowable positioning time. In this case, the second end decision
component 133 uses the positioning result for pattern matching
positioning as the position of the cellular terminal 20. By making
the above decisions, a more precise positioning result can be
obtained by pattern matching positioning. The above-mentioned
thresholds .sigma..sub.T and T may be determined by the same method
as with the first end condition determination component 125
discussed above, using the table of FIG. 3 and based on requirement
information and environment information.
[0103] As discussed above, if the second end decision component 133
decides to end the estimation of the position of the cellular
terminal 20, it sends a signal that halts positioning processing to
the cellular terminal 20 via the transceiver 11. Specifically, it
sends a signal that halts the measurement of MR. Also, the second
end decision component 133 outputs information indicating the
position of the cellular terminal 20 estimated as above,
corresponding to the usage details, such as sending it to the
cellular terminal 20.
[0104] In the above-mentioned decision, if it is decided not to end
the estimation of the position of the cellular terminal 20 (if it
is not decided to end it), the second end decision component 133
instructs the second base station positioning calculator 132 to
perform pattern matching positioning computation on the basis of
new MR acquired at a different timing from that of the MR used in
the pattern matching positioning performed by the second base
station positioning calculator 132. Specifically, when new MR is
acquired by the second reception state information acquisition
component 131, the second base station positioning calculator 132
is instructed to use that MR as well to perform pattern matching
positioning computation of the cellular terminal 20. However,
active control of the second base station positioning calculator
132 from the second end decision component 133 does not necessarily
have to be performed, and the system may be such that pattern
matching positioning computation is performed by not performing
positioning end processing as above.
[0105] The indoor/outdoor determination component 134 is second
indoor/outdoor determination means for determining whether the
cellular terminal 20 is indoors or outdoors on the basis of the MR
inputted from the second reception state information acquisition
component 131. The indoor/outdoor determination component 134 has
the same function as that of the indoor/outdoor determination
component 124 of the first positioning component 12. The
indoor/outdoor determination component 134 outputs the result of
determining whether the cellular terminal 20 is indoors or outdoors
to the second positioning controller 135 shown in FIG. 1.
[0106] The second positioning controller 135 is second positioning
control means for controlling the execution of GPS positioning of
the cellular terminal 20 on the basis of the result of deciding the
approximate position by the second end decision component 133 and
the result of determination by the indoor/outdoor determination
component 134. More specifically, the second positioning controller
135 does not execute any positioning control when positioning is
ended as a result of the decision by the second end decision
component 133 about the approximate position.
[0107] If the result of deciding the approximate position by the
second end decision component 133 is that positioning is not ended,
and the result of determination by the indoor/outdoor determination
component 134 is that the cellular terminal 20 is located outdoors,
then the second positioning controller 135 controls so as to
execute GPS positioning of the cellular terminal 20. In that case,
more specifically, the second positioning controller 135 sends a
control signal to the cellular terminal 20 that executes GPS
positioning. Alternatively, if the reception of a signal from the
GPS satellite 40, GPS positioning computation, and MR measurement
have already been performed, which are processing for positioning
in the cellular terminal 20, then the second positioning controller
135 may send the cellular terminal 20 a signal that does not halt
processing for GPS positioning (reception of signals from the GPS
satellite 40 and GPS positioning computation), but does halt
processing other than GPS positioning (MR measurement).
[0108] On the other hand, if the result of deciding the approximate
position by the second end decision component 133 is that
positioning is not ended, and the result of determination by the
indoor/outdoor determination component 134 is that the cellular
terminal 20 is located outdoors, then the second positioning
controller 135 controls so as to execute pattern matching
positioning of the cellular terminal 20. As mentioned above, since
pattern matching positioning is performed with calculation of the
approximate position as well, the second positioning controller 135
does not halt this processing (no need for active control).
[0109] Alternatively, active control may be performed such that the
second positioning controller 135 sends the cellular terminal 20 a
control signal to acquire MR and send it to the positioning server
10, and pattern matching positioning computation is performed by
the second base station positioning calculator 132 once MR is
received by the positioning server 10. Alternatively, if the
reception of a signal from the GPS satellite 40, GPS positioning
computation, and MR measurement have already been performed, which
are processing for positioning in the cellular terminal 20, then
the second positioning controller 135 may send the cellular
terminal 20 a signal that does not halt processing for pattern
matching positioning (MR measurement), but does halt processing
other than pattern matching positioning (reception of a signal from
the GPS satellite 40 and GPS positioning computation). The above is
the functional configuration of the positioning server 10.
[0110] FIG. 6 shows the hardware configuration of the positioning
server 10. As shown in FIG. 6, the positioning server 10 is
constituted to include a computer that comprises a CPU 101, a RAM
102 and ROM 103 (main storage devices), a communication module 104
for performing communication, a hard disk or other such auxiliary
storage device 105, and other such hardware. These constituent
elements operate under programs or the like, thereby exhibiting the
functions of the positioning server 10.
[0111] Next, the indoor/outdoor determination processing
(indoor/outdoor determination method) executed by the
indoor/outdoor determination component 124, 134 in this embodiment
will be described through reference to the flowchart of FIG. 7.
This processing is executed, for example, in an indoor/outdoor
determination step (S203 in FIGS. 11 and 12, and S305 in FIG. 13)
by the indoor/outdoor determination component 124, 134 in
positioning processing (FIGS. 11 to 13) as discussed below.
[0112] First, at the indoor/outdoor determination component 124,
134, the reception component 52 receives from the cellular terminal
20 MR that includes information for identifying the emission source
of the received signal (S21 in FIG. 7), and the specification
component 53 counts the number of pieces of emission source
identification information included in the received MR and thereby
specifies the emission source number N of the received signal
(S22). For example, if there are two pieces of emission source
identification information included in the received MR, "BTS-A" and
"BTS-B," the emission source number N is specified as "2." As to
the emission source, received signals belonging to the same cell
may be taken to be received signals from the same emission source,
or received signals from different sectors belonging to the same
cell may be taken to be received signals from different emission
sources.
[0113] The possibility determination component 54 determines
whether or not the emission source number N is equal to or greater
than the minimum emission source number M at which indoor/outdoor
determination is possible on the basis of a first indoor/outdoor
determination method (S23).
[0114] In S23, if the emission source number N is equal to or
greater than the minimum emission source number M, it can be
decided that indoor/outdoor determination is possible on the basis
of the first indoor/outdoor determination method, so the first
indoor/outdoor determination component 55 executes indoor/outdoor
determination on the basis of the first indoor/outdoor
determination method (S24). To give an example of this, the
approximate position of the cellular terminal 20 is calculated by
referring to a positioning database (not shown) in which the MR
from the cellular terminal 20 has been stored in advance, and a
determination of indoors or outdoors is made on the basis of
whether or not there is a contradiction between the measurement
data in the MR and the predicted data in the approximate position.
The extent P of being indoors is calculated from the magnitude of
the contradiction between the measurement data M and the predicted
data D in the approximate position. For instance, P=(D-M)/M, where
a value less than zero is considered to be zero, and a value
greater than 1 is considered to be 1.
[0115] On the other hand, in S23, if the emission source number N
is less than the minimum emission source number M, it can be
decided that indoor/outdoor determination is impossible on the
basis of the first indoor/outdoor determination method, so the
second indoor/outdoor determination component 56 executes
indoor/outdoor determination on the basis of the following second
indoor/outdoor determination method.
[0116] The second indoor/outdoor determination component 56
extracts from the determination database 51 combined information
including all of the emission source identification information
included in the MR, and GPS possibility information corresponding
to this combined information, and sets the lowest number of
emission sources included in the extracted combined information as
the minimum emission source number Q (S25).
[0117] To give a specific example, as shown in FIG. 8, if the
emission source identification information (BTS-A, BTS-B) is
included in the MR, three combined information sets consisting of
(BTS-A, BTS-B, BTS-D), (BTS-A, BTS-B, BTS-E), and (BTS-A, BTS-B),
and GPS possibility information corresponding to these, are
extracted from the determination database 51 as the combined
information including all of this emission source identification
information (BTS-A and BTS-B). The lowest value "2" out of the
numbers of emission sources included in the above-mentioned three
sets of combined information ("3," "3," and "2" here) is set as the
minimum emission source number Q.
[0118] To give another example, if the emission source
identification information (BTS-A, BTS-E) is included in the MR,
two combined information sets consisting of (BTS-A, BTS-C, BTS-E,
BTS-G) and (BTS-A, BTS-B, BTS-E), and GPS possibility information
corresponding to these, are extracted from the determination
database 51 as the combined information including all of this
emission source identification information (BTS-A and BTS-E). The
lowest value "3" out of the numbers of emission sources included in
the above-mentioned two sets of combined information ("4" and "3"
here) is set as the minimum emission source number Q.
[0119] Next, the second indoor/outdoor determination component 56
determines whether or not the emission source number N is equal to
or greater than the minimum emission source number Q (S26). If the
emission source number N is equal to or greater than the minimum
emission source number Q in S26, it can be decided that the
cellular terminal 20 has received a signal from at least the
minimum emission source number Q of emission sources, so it is
concluded that the cellular terminal 20 is outdoors. In view of
this, it is checked to see if there is GPS possibility information
corresponding to the same combined information as the combination
of emission source identification information included in the MR
(S27), and if there is GPS possibility information, indoors or
outdoors is determined on the basis of this GPS possibility
information (S29). If there is no GPS possibility information, it
is determined that the cellular terminal 20 is outdoors (S28). If
there is GPS possibility information, when a determination about
indoors or outdoors is made on the basis of this GPS possibility
information, the degree of matching to this GPS possibility
information is used as the extent to which the cellular terminal 20
is indoors. If there is no GPS possibility information, the extent
P to which the cellular terminal 20 is outdoors is calculated from
the difference between N and Q. For example, P=A(Q-N)/N, where if P
is over 1 it is treated as 1, and if under zero it is treated as
zero. A is a coefficient, and is a system parameter.
[0120] On the other hand, if the emission source number N is less
than the minimum emission source number M in S26, it is checked to
see if there is GPS possibility information corresponding to the
same combined information as the combination of emission source
identification information included in the MR (S30), and if there
is GPS possibility information, indoors or outdoors is determined
on the basis of this GPS possibility information (S29). If there is
no GPS possibility information, it is determined whether or not the
emission source number N is less than the minimum emission source
number P at which indoor/outdoor determination is possible on the
basis of the second indoor/outdoor determination method (S31), and
if the emission source number N is less than the minimum emission
source number P, it is determined that indoor/outdoor determination
is impossible on the basis of the second indoor/outdoor
determination method (S33). On the other hand, if the emission
source number N is equal to or greater than the minimum emission
source number P, it is determined that indoor/outdoor determination
is possible on the basis of the second indoor/outdoor determination
method, but that the cellular terminal 20 is indoors since it can
be decided that the cellular terminal 20 has not received a signal
from at least the minimum emission source number M of emission
sources, and the reception state is inferior (S32).
[0121] As discussed above, a determination result as to whether the
cellular terminal 20 is indoors or outdoors, or whether it cannot
be determined, can be quickly obtained by the indoor/outdoor
determination processing in FIG. 7.
[0122] As discussed above, with the positioning server 10
pertaining to this embodiment, the execution of indoor/outdoor
determination based on the first indoor/outdoor determination
method is controlled on the basis of the result of comparing the
emission source number N and the minimum emission source number M,
and if the execution of indoor/outdoor determination based on the
first indoor/outdoor determination method is impossible, it is
possible to switch quickly to execution of indoor/outdoor
determination based on the second indoor/outdoor determination
method. Also, in indoor/outdoor determination based on the second
indoor/outdoor determination method, if there is GPS possibility
information, a determination of indoors or outdoors can be properly
made on the basis of this GPS possibility information, and if there
is no GPS possibility information, a determination of indoors or
outdoors can be properly made on the basis of the emission source
number N, the minimum emission source number Q, and the minimum
number of emission sources P at which the second indoor/outdoor
determination method is possible.
[0123] The determination database 51 can be configured as follows,
for example. First, the determination database 51 can be configured
by extracting the necessary information (GPS possibility
information or information identifying the emission source of a
received signal) from a positioning database (not shown) that
stores information included in the MR (such as information
identifying the emission source of a received signal, the received
signal level, information indicating the signal transmission delay,
information indicating the amount of attenuation, and information
about whether GPS positioning is possible). The above-mentioned
positioning database may also be utilized directly as a
determination database.
[0124] Second, the determination database 51 can be configured
using measurement information obtained in the course of configuring
a positioning database and ordinary positioning. This second method
can be divided into two types: a method that uses measurement data
and a method that uses prediction data.
[0125] Of these, a method that uses measured data involves creating
a database by linking the emission source identification
information measured at the cellular terminal to whether or not GPS
positioning is possible. For example, as shown in (a) of FIG. 9,
MR1, MR2, and MR3 including measurement data are received, a
database is created by linking a combination of emission source
identification information from MR1 and MR2 (BTS-A, BTS-BBTS-C) to
information that GPS positioning is possible, and a database is
created by linking a combination of emission source identification
information from MR3 (BTS-A, BTS-D) to information that GPS
positioning is impossible, thereby configuring the determination
database in (a) of FIG. 9.
[0126] Meanwhile, a method that uses prediction data involves
assuming that the entire grid (the individual places resulting from
dividing the measured area into a mesh pattern) is outdoors,
producing prediction data from a propagation prediction formula
that takes into account the landscape and surrounding obstructions
for each grid, and creating a database. For example, as shown in
(b) of FIG. 9, the received signal strength of all surrounding
emission sources in a certain grid (position: POS1) is calculated
by a predetermined propagation prediction formula (S41), and it is
determined whether or not that emission source signal can be
received, according to a predetermined method, with respect to the
overall predicted received signal strength (S42). For example, a
predetermined noise level is used as a reference, and if the
reception strength is higher than this noise level, it is
determined that the emission source signal can be received, but if
the reception strength is equal to or less than this noise level,
it is determined that the emission source signal cannot be
received. The combination of identifiers for the emission sources
for which reception was deemed possible is stored in the
determination database (S43). Thereafter, steps S41 to S43 are
executed for each grid to configure a determination database.
[0127] Next, the positioning processing (positioning method)
executed by the positioning system 1 pertaining to this embodiment
will be described through reference to the flowchart of FIGS. 10 to
13. First, the overall positioning processing executed by the
positioning system 1 pertaining to this embodiment will be
described through reference to the flowchart in FIG. 10. This
processing is commenced when the positioning server 10 receives a
request from the cellular terminal 20 for positioning via the
cellular communication network. However, the positioning processing
may instead be triggered by something else.
[0128] First, the cell ID of the cellular base station 30 that is
the emission source of the received radio wave is measured by the
cellular communication component 21 of the cellular terminal 20,
and information about this cell ID is sent from the cellular
communication component 21 to the positioning server 10. At the
positioning server 10, the cell ID is received by the cell ID
positioning component 16 via the transceiver 11 (S101, an emission
source positioning step).
[0129] Next, the radius R of the cell pertaining to the cell ID is
estimated by the cell ID positioning component 16 (S102, an
emission source positioning step). The values of the estimated
radius R and a previously stored threshold dr are then compared by
the second base station positioning calculator 132 (S103, an
emission source positioning step). If the estimated radius is below
the threshold dr, it can be estimated that the cellular terminal 20
is located at the position of that cell (the position of the
cellular base station 30), and that cell ID is used as the
positioning result. If it is decided that the estimated radius is
not below the threshold dr, then the positioning result is that the
position cannot be estimated from the cell ID. The above-mentioned
positioning result produced by the base station positioning
calculator 13 is inputted to the end decision component 14.
[0130] Next, the cell ID positioning component 16 decides whether
or not to end the estimation of the position of the cellular
terminal 20 on the basis of the positioning result. If the
positioning result is to the effect that positioning could be
performed on the basis of the cell ID, it is decided that the
estimation of the position of the cellular terminal 20 is to be
ended, then the positioning result produced by cell ID is used as
the final positioning result, and the positioning processing is
ended (S104, an emission source positioning step).
[0131] On the other hand, if the positioning result is to the
effect that positioning cannot be performed on the basis of cell
ID, the cell ID positioning component 16 decides not to end the
estimation of the position of the cellular terminal 20. In that
case, a signal that starts processing for pattern matching
positioning is sent through the transceiver 11 to the cellular
terminal 20 (S45). If the elapsed time of the positioning is used
for the decision, the positioning elapsed time is counted from this
point in the positioning server 10. In this case, positioning by
the hybrid algorithm 1 or the hybrid algorithm 2 is then carried as
follows.
[0132] With the positioning server 10, requirement information
indicating a requirement with respect to the estimation of the
position of the cellular terminal 20 is inputted to the requirement
information input component 14 (S105, requirement information input
step). More specifically, for example, the requirement information
input component 14 requests that the cellular terminal 20 transmit
requirement information, and the requirement information
accordingly transmitted from the cellular terminal 20 is received
by the requirement information input component 14. The requirement
information is outputted from the requirement information input
component 14 to the positioning method determination component
15.
[0133] Then, whether to execute the hybrid algorithm 1 or the
hybrid algorithm 2 is determined by the positioning method
determination component 15 on the basis of the requirement
information inputted from the requirement information input
component 14 (S106, positioning method determination step). The
determination of the positioning method is carried out by referring
to the information in the table of FIG. 3 as discussed above.
[0134] If the above determination is that the hybrid algorithm 1 is
to be executed, the execution of positioning by the first
positioning component 12 is controlled by the positioning method
determination component 15, and positioning by the hybrid algorithm
1 is performed by the first positioning component 12 (S107,
positioning method determination step, first positioning step).
[0135] On the other hand, if it is determined that the hybrid
algorithm 2 is to be executed, the execution of positioning by the
second positioning component 13 is controlled by the positioning
method determination component 15, and positioning by the hybrid
algorithm 2 is performed by the second positioning component 13
(S108, positioning method determination step, second positioning
step). The above is the overall positioning processing executed by
the positioning system 1 pertaining to this embodiment.
[0136] Positioning processing by the hybrid algorithm 1 and by the
hybrid algorithm 2 will now be described. First, positioning
processing by the hybrid algorithm 1 (S107) will be described
through reference to the flowchart in FIG. 12.
[0137] First, a signal that starts processing for pattern matching
positioning and GPS positioning is sent from the first positioning
component 12 through the transceiver 11 to the cellular terminal 20
(S201, the first position estimation step). The positioning elapsed
time is counted from this point in the positioning server 10.
[0138] At the cellular terminal 20, this signal is received, which
triggers the reception of a signal from the GPS satellite 40 by the
GPS reception component 22 and the start of GPS positioning
computation (AGPS positioning) by the GPS positioning computer 23
(S201, the position estimation step). At the cellular terminal 20,
if the AGPS positioning by the GPS reception component 22 and the
GPS positioning computer 23 has succeeded (that is, if a
positioning result of a specific precision has been obtained) or
failed, information about the positioning result is sent to the
positioning server 10. At the positioning server 10, the
information about the positioning result produced by AGPS
positioning is received by the first end decision component 123 of
the first positioning component 12 through the transceiver 11.
[0139] With the cellular terminal 20, this signal is received,
reception state information indicating the reception state of the
radio wave is measured by the cellular communication component 21,
and this information is sent as MR to the positioning server 10.
The reception state information continues to be measured (such as
at regular intervals) at the cellular terminal 20 even after the MR
transmission, and this information is sent as MR to the positioning
server 10. Then, at the positioning server 10, the MR is received
by the first reception state information acquisition component 121
via the transceiver 11 (S202, a reception state information
acquisition step). The MR received by the first reception state
information acquisition component 121 is outputted to the
indoor/outdoor determination component 124 and the first base
station positioning calculator 122.
[0140] Then, the indoor/outdoor determination component 124
determines whether or not the cellular terminal 20 is indoors or
outdoors on the basis of the MR inputted from the reception state
information acquisition component 12 (S203, an indoor/outdoor
determination step). The result of determination by the
indoor/outdoor determination component 124 is outputted to the
first end condition determination component 125. Then, the first
end condition determination component 125 determines the specific
end condition used in the decision by the first end decision
component 123 on the basis of the result of determination by the
indoor/outdoor determination component 124. More specifically, the
pattern matching positioning error threshold .sigma..sub.T and the
positioning elapsed time threshold T are determined (S204, a first
end condition determination step). Information indicating the
determined specific end condition is outputted to the first end
decision component 123.
[0141] Then, pattern matching positioning computation is performed
by the first base station positioning calculator 122 on the basis
of the MR inputted from the first reception state information
acquisition component 121, the position of the cellular terminal 20
is estimated, and the positioning error is calculated (S205, a
first position estimation step). The positioning result and
positioning error produced by pattern matching positioning are
outputted from the first base station positioning calculator 122 to
the first end decision component 123.
[0142] Then, the first end decision component 123 decides whether
or not AGPS positioning has ended (S206, a first end decision
step). This decision is made according to whether the positioning
result produced by AGPS positioning from the cellular terminal 20
(one in which positioning of a specific precision has succeeded) is
inputted to the first end decision component 123. If it is decided
that the AGPS positioning has ended, the first end decision
component 123 decides to end the estimation of the position of the
cellular terminal 20. In that case, the positioning result produced
by AGPS positioning is used as the final positioning result, and
the positioning processing is ended (S207).
[0143] If it is decided that the AGPS positioning has not ended,
then the first end decision component 123 decides whether or not
the positioning elapsed time is above the threshold T (S208, a
first end decision step). If it is decided that the positioning
elapsed time is above the threshold T, the first end decision
component 123 decides to end the estimation of the position of the
cellular terminal 20. In that case, the positioning result produced
by pattern matching positioning (the new result obtained in S205)
is used as the final positioning result, and positioning processing
is ended (S209).
[0144] If it is decided that the positioning elapsed time is not
above the threshold T, the first end decision component 123 decides
whether or not the positioning error of the positioning result
produced by pattern matching positioning (the new result obtained
in S205) is below the threshold .sigma..sub.T (S210, a first end
decision step). If it is decided that the positioning error is
below the threshold .sigma..sub.T, the end decision component 123
decides to end the estimation of the position of the cellular
terminal 20. In that case, the positioning result produced by
pattern matching positioning (the new result obtained in S205) is
used as the final positioning result, and positioning processing is
ended (S211).
[0145] If it is decided that the positioning error is not below the
threshold .sigma..sub.T, MR is again received by the first
reception state information acquisition component 121 via the
transceiver 11 according to transmission from the cellular terminal
20 (S202), and the same processing as above is repeated.
[0146] If the first end decision component 123 decides to end the
estimation of the position of the cellular terminal 20 as described
above (S207, S209, S211), a signal that halts processing for
positioning is sent from the first end decision component 123
through the transceiver 11 to the cellular terminal 20. When this
signal is received at the cellular terminal 20, processing for
positioning is halted. Further, the information indicating the
final positioning result (information indicating the estimated
position of the cellular terminal 20) is outputted corresponding to
the usage details, such as sending it to the cellular terminal
20.
[0147] The order of the processing of the decision about ending
positioning in S208 and S210 above may be reversed. That is, the
decision (S208) as to whether or not the positioning error of the
positioning result produced by pattern matching positioning (S210)
is below the threshold .sigma..sub.T may be made before the
decision as to whether or not the positioning elapsed time is above
the threshold T.
[0148] Next, another example of the positioning processing will be
described through reference to the flowchart of FIG. 12. In the
processing described through reference to the flowchart of FIG. 11
in the decision about ending positioning (S206, S208, S210), if it
was decided not to end positioning, MR was acquired again (S202),
indoor/outdoor determination was performed (S203), and the
threshold .sigma..sub.T for positioning error of pattern matching
and the threshold T for positioning elapsed time were determined
(S204) on the basis of this. However, the indoor/outdoor
determination (S203) and the determination of the threshold
.sigma..sub.T for positioning error of pattern matching and the
threshold T for positioning elapsed time (S204) do not necessarily
have to be performed for every repetition, and may only be
performed once.
[0149] Specifically, as shown in the flowchart of FIG. 12, in the
decision about ending positioning (S206, S208, S210), if it is
decided not to end positioning, MR is again received by the
reception state information acquisition component 121 via the
transceiver 11 according to transmission from the cellular terminal
20 (S212, a first reception state information acquisition step).
The MR received by the first reception state information
acquisition component 121 is outputted to the base station
positioning calculator 122.
[0150] Then, pattern matching positioning computation is performed
by the first base station positioning calculator 122 on the MR
inputted from the first reception state information acquisition
component 121, the position of the cellular terminal 20 is
estimated, and the positioning error is calculated (S205, a first
position estimation step). Subsequent processing is similar to the
processing shown in the flowchart in FIG. 11.
[0151] If the indoor/outdoor determination is not to be put in a
repeating loop as above, the calculated amount can be reduced. In
this case, however, it is possible that the positioning performance
will be lower than with the processing shown in the flowchart of
FIG. 11. The above is the positioning processing by the hybrid
algorithm 1.
[0152] The positioning processing by the hybrid algorithm 2 (S108)
will now be described through reference to the flowchart in FIG.
14.
[0153] First, a signal that starts processing for pattern matching
positioning is sent from the second positioning component 13
through the transceiver 11 to the cellular terminal 20 (S301). If
the elapsed time of the positioning is used for the decision, the
positioning elapsed time is counted from this point in the
positioning server 10.
[0154] With the cellular terminal 20, this signal is received,
reception state information indicating the reception state of the
radio wave is measured by the cellular communication component 21,
and this information is sent as MR to the positioning server 10.
The reception state information continues to be measured (such as
at regular intervals) at the cellular terminal 20 even after the MR
transmission, and this information is sent as MR to the positioning
server 10. Then, at the positioning server 10, the MR is received
by the second reception state information acquisition component 131
via the transceiver 11 (S301, a second reception state information
acquisition step). The MR received by the second reception state
information acquisition component 131 is outputted to the
indoor/outdoor determination component 134 and the second base
station positioning calculator 132.
[0155] Then, pattern matching positioning computation is performed
by the second base station positioning calculator 132 on the basis
of the MR inputted from the second reception state information
acquisition component 131, the approximate position of the cellular
terminal 20 is estimated, and the positioning error is calculated
(S302, a second approximate position estimation step). The
positioning result and positioning error produced by pattern
matching positioning are outputted from the second base station
positioning calculator 132 to the second end decision component
133.
[0156] Next, the second end decision component 133 decides whether
or not the positioning error is less than a threshold (S303, a
second end decision step). If it is decided that the positioning
error is below the threshold, the second end decision component 133
decides to end the estimation of the position of the cellular
terminal 20. In that case, the approximate position is used as the
final positioning result, and the positioning processing is ended
(S304). If the second end decision component 133 decides to end the
estimation of the position of the cellular terminal 20, a signal
that halts processing for positioning is sent from the second end
decision component 133 through the transceiver 11 to the cellular
terminal 20. When this signal is received by the cellular terminal
20, processing for positioning is halted.
[0157] If it is decided that the positioning error is not below the
threshold, a notification to this effect is sent from the second
end decision component 133 to the indoor/outdoor determination
component 134. Then, the indoor/outdoor determination component 134
determines whether the cellular terminal 20 is indoors or outdoors
on the basis of the MR inputted from the second reception state
information acquisition component 131 (S305, a second
indoor/outdoor determination step). The result of determination by
the indoor/outdoor determination component 134 is outputted to the
positioning controller 135.
[0158] Next, the second positioning controller 135 controls the
positioning method of the cellular terminal 20 on the basis of the
result of determination by the indoor/outdoor determination
component 134 (S306, a second positioning control step). If the
result of determination by the indoor/outdoor determination
component 134 is that the cellular terminal 20 is located outdoors,
then the second positioning controller 135 performs control so that
the GPS positioning of the cellular terminal 20 is executed (S307,
a second positioning control step). More specifically, the second
positioning controller 135 sends a control signal that executes GPS
positioning on the cellular terminal 20.
[0159] At the cellular terminal 20, this signal is received, which
triggers the reception of a signal from the GPS satellite 40 by the
GPS reception component 22 and the start of GPS positioning
computation (AGPS positioning) by the GPS positioning computer 23
(S307, the second positioning control step). At the cellular
terminal 20, if the AGPS positioning by the GPS reception component
22 and the GPS positioning computer 23 has succeeded (that is, if a
positioning result of a specific precision has been obtained) or
failed, information about the positioning result is sent to the
positioning server 10. At the positioning server 10, the
information about the positioning result produced by AGPS
positioning is received by the second end decision component 133
through the transceiver 11.
[0160] At the positioning server 10, the second end decision
component 133 decides whether or not the AGPS positioning has
succeeded (that is, whether or not the AGPS positioning is fixed)
(S53). This decision is made according to whether the positioning
result produced by AGPS positioning from the cellular terminal 20
(one in which position of a specific precision has succeeded) is
inputted to the second end decision component 133. If it is decided
that the AGPS positioning has succeeded, the positioning result
produced by AGPS positioning is used as the final positioning
result, and the positioning processing is ended (S309). If it is
decided that the AGPS positioning has not succeeded, the
approximate position is used as the final positioning result, and
positioning processing is ended (S304).
[0161] On the other hand, if the result of determination by the
indoor/outdoor determination component 134 in S306 is that the
cellular terminal 20 is located indoors, the second positioning
controller 135 performs control so that pattern matching
positioning of the cellular terminal 20 is executed. More
specifically, after S301, reception state information is measured
at the cellular terminal 20, and this information is sent as MR to
the positioning server 10. Then, at the positioning server 10, the
MR is received by the second reception state information
acquisition component 131 via the transceiver 11 (S310, a second
positioning control step). The MR received by the second reception
state information acquisition component 131 is outputted to the
second base station positioning calculator 132.
[0162] Then, pattern matching positioning computation is performed
by the second base station positioning calculator 132 on the new MR
inputted from the second reception state information acquisition
component 131, the position of the cellular terminal 20 is
estimated, and the positioning error is calculated (S311, a second
positioning control step). The positioning result and positioning
error produced by pattern matching positioning are outputted from
the second base station positioning calculator 132 to the second
end decision component 133. When the positioning result from the
second base station positioning calculator 132 is inputted to the
second end decision component 133, it is decided to end the
estimation of the position of the cellular terminal 20. In this
case, the second end decision component 133 uses the positioning
result of pattern matching positioning as the position of the
cellular terminal 20 (S312). Alternatively, a decision may be made
by the second end decision component 133 as follows. It is decided
whether or not the positioning error of the positioning result
obtained by pattern matching positioning computation performed by
the second base station positioning calculator 132 is below a
threshold .sigma..sub.T, and it is decided whether or not to end
the estimation of the position of the cellular terminal 20.
[0163] If it is decided by the second end decision component 133
that the positioning error is below the threshold .sigma..sub.T, it
is decided to end the estimation of the position of the cellular
terminal 20. This means that positioning is ended when the
positioning result obtained by the pattern matching positioning
computation performed by the second base station positioning
calculator 132 satisfies a specific measurement precision. In this
case, the second end decision component 133 uses the positioning
result of pattern matching positioning as the position of the
cellular terminal 20 (S312).
[0164] If it is decided that the positioning error is not below the
threshold .sigma..sub.T, the second end decision component 133
decides whether or not the positioning elapsed time is above the
threshold T, and decides whether or not to end the estimation of
the position of the cellular terminal 20. If the second end
decision component 133 decides that the positioning elapsed time is
above the threshold T, it is decided to end the estimation of the
position of the cellular terminal 20. In this case, the end
decision component 133 uses the positioning result of pattern
matching positioning as the position of the cellular terminal 20
(S312).
[0165] If the second end decision component 133 decides to end the
estimation of the position of the cellular terminal 20, a signal
that halts processing for positioning is sent from the second end
decision component 133 through the transceiver 11 to the cellular
terminal 20. When this signal is received at the cellular terminal
20, processing for positioning (MR measurement and transmission) is
ended.
[0166] If it is decided that the positioning error is not below the
threshold .sigma..sub.T, and it is decided that the positioning
elapsed time is not above the threshold T, then MR is again
received by the second reception state information acquisition
component 131 through the transceiver 11 according to the
transmission from the cellular terminal 20, pattern matching
positioning computation is performed by the second base station
positioning calculator 132 (S310, S311), and the same processing as
above is repeated (repeated processing is not depicted).
[0167] The information indicating the final positioning result
(information indicating the estimated position of the cellular
terminal 20) obtained as above (S304, S309, S312) is outputted
corresponding to the usage details, such as sending it to the
cellular terminal 20. The above-described is positioning processing
by the hybrid algorithm 1.
[0168] As discussed above, in this embodiment a positioning method
corresponding to requirement information is decided and executed
from among two positioning methods each having a different
positioning time and positioning precision. As discussed above,
with this embodiment, it is decided whether the cellular terminal
20 is indoors or outdoors on the basis of MR measured by the
cellular terminal 20, and a positioning end condition is determined
on the basis of this decision. For example, in a suburban setting,
the AGPS precision outdoors must be taken into account and
.sigma..sub.T reduced, but indoors there will be problems at the
same .sigma..sub.T. The result of pattern matching positioning in
the suburbs is far inferior to that with AGPS because there are
fewer cellular base stations 30 (radio wave emission sources).
Therefore, if a .sigma..sub.T that is close to the precision of
AGPS is used, pattern matching positioning will not be fixed in
most places, and positioning processing will end up being continued
until there is a time-out. Conversely, if .sigma..sub.T is
increased, there will be no positioning result by AGPS positioning
outdoors, and the result of pattern matching positioning will be
low in precision. As a result, the overall positioning precision
might be significantly deteriorated.
[0169] As discussed above, the end condition for positioning can be
selected according to the situation, that is, if it is believed
that the cellular terminal 20 is outdoors and higher positioning
precision will be obtained by taking a relatively long time for
positioning, or if it is believed that the receiver is indoors and
higher positioning precision will not be obtained even if a
relatively long time is taken for positioning. Thus, with this
embodiment, positioning can be performed at the proper positioning
precision and in the proper positioning time according to whether
the receiver is indoors or outdoors.
[0170] With the other hybrid algorithm 2, the approximate position
of the cellular terminal 20 is estimated and the precision of this
approximate position is calculated on the basis of MR measured by
the cellular terminal 20. It is decided whether or not to end the
estimation of the position of the receiver on the basis of the
precision of this approximate position. Therefore, as long as the
precision of the approximate position is sufficiently high, GPS
positioning is not performed at this point, and the estimation of
the position of the cellular terminal 20 is ended. Meanwhile, with
the positioning system 1 pertaining to this embodiment, it is
determined whether the cellular terminal 20 is indoors or outdoors
on the basis of MR measured by the cellular terminal 20. The
execution of GPS positioning is controlled on the basis of the
decision as to whether or not to end the estimation of the position
of the cellular terminal 20, and the determination as to whether
the cellular terminal 20 is indoors or outdoors.
[0171] Therefore, if the cellular terminal 20 has adequate
precision of the approximate position without GPS positioning being
performed, or if it is in a state in which GPS positioning is
difficult to perform, it does not execute GPS positioning, but
otherwise it can perform control that executes GPS positioning,
etc. Also, as discussed above, with the positioning system 1,
control about whether or not GPS positioning can be executed can be
performed without actually performing GPS positioning, which takes
a long time to decide whether or not it can be performed.
Specifically, with the positioning system 1 pertaining to this
embodiment, a positioning result that corresponds to the state of
the receiver can be obtained in less time.
[0172] As above, with the hybrid algorithm 1, the threshold
.sigma..sub.T and the threshold T are determined on the basis of
indoor/outdoor determination, so the positioning precision and
positioning time can be optimized. On the other hand, since the
function of GPS positioning operates constantly every time
positioning is performed by the cellular terminal 20, the cellular
terminal 20 consumes more power (more battery consumption). The
hybrid algorithm 2 switches between GPS positioning and pattern
matching positioning, so the positioning time and positioning
precision cannot be optimized, but since the function of GPS
positioning operates only when needed, the cellular terminal 20
consumes less power than with the hybrid algorithm 1. Also, if an
approximated position has sufficient precision, the positioning
processing is shut down at that point, so the positioning time is
shorter. With this embodiment, either the hybrid algorithm 1 or the
hybrid algorithm 2 is selected according to the requirement with
respect to positioning, so positioning can be performed at the
proper positioning time and positioning precision according to the
application type and settings
[0173] Also, it is preferable for the positioning based on MR to be
pattern matching positioning as in this embodiment. With this
constitution, the position of the cellular terminal 20 can be
estimated reliably and properly on the basis of MR. However, the
positioning method based on MR does not necessarily have to entail
pattern matching, and instead, for example, the distance between
the various cellular base stations 30 and the cellular terminal 20
may be found on the basis of RTT, and the position of the cellular
terminal 20 estimated on this basis.
[0174] Also, as in this embodiment, it is preferable if the end
condition determined by the first end condition determination
component 125 is the threshold .sigma..sub.T of positioning result
error and/or the threshold T of the elapsed time of positioning.
With this constitution, the positioning end condition can be
determined reliably and properly. However, another end condition
besides this may be used instead.
[0175] Also, it is preferable for positioning based on cell ID to
be performed at the beginning of the overall positioning processing
as in this embodiment. With this constitution, for example, if the
cellular terminal 20 is in a place where the cellular base station
30 are located close together, or another such environment, the
positioning result can be acquired easily. Positioning based on
cell ID does not necessarily have to be performed, however.
[0176] Also, if, in the hybrid algorithm 2, pattern matching
positioning is performed when the cellular terminal 20 is located
indoors and GPS positioning is not to be performed, as in this
embodiment, then the positioning result of the cellular terminal 20
can be obtained even though GPS positioning is not performed.
[0177] In this embodiment, request information input, positioning
method determination, pattern matching positioning computation,
indoor/outdoor determination, end condition determination,
positioning method control, decision to end the positioning
processing, and so forth were performed by the positioning server
10, but all of these may instead be performed at the cellular
terminal 20. Specifically, the positioning system 1 may be the
cellular terminal 20 itself. Conversely, the positioning system 1
may be the positioning server 10 itself. In that case, the
positioning server 10 receives all information for performing
positioning computation from the cellular terminal 20. For example,
AGPS positioning computation may be performed by the positioning
server 10.
[0178] The two modification examples given below may be employed as
embodiments of the indoor/outdoor determination component 124, 134.
In the first modification example, the determination database 51
does not store indoor/outdoor characteristic information (GPS
possibility information in the above embodiment), and
indoor/outdoor determination based on indoor/outdoor characteristic
information is not performed. In the second modification example,
indoor/outdoor determination based on indoor/outdoor characteristic
information is not performed, nor is indoor/outdoor determination
based on the first indoor/outdoor determination method. These
modification examples will now described in order.
First Modification Example
[0179] The functional configuration of the indoor/outdoor
determination component 124, 134 in the first modification example
is the same as the functional configuration shown in FIG. 4 and
discussed above, but the indoor/outdoor determination processing
(indoor/outdoor determination method) is expressed by the flowchart
in FIG. 14. Specifically, in the indoor/outdoor determination
processing in the first modification example, first the reception
component 52 of the indoor/outdoor determination component 124, 134
receives from the cellular terminal 20 MR including emission source
identification information about the received signal (S21 in FIG.
14), and the specification component 53 counts the number of pieces
of emission source identification information included in the
received MR, and thereby specifies the emission source number N of
the received signal (S22). Next, the possibility determination
component 54 determines whether or not the emission source number N
is equal to or greater than the minimum emission source number M at
which indoor/outdoor determination based on the first
indoor/outdoor determination method is possible (S23).
[0180] In S23, if the emission source number N is equal to or
greater than the minimum emission source number M, it can be
decided that indoor/outdoor determination based on the first
indoor/outdoor determination method is possible, so the first
indoor/outdoor determination component 55 executes indoor/outdoor
determination on the basis of the first indoor/outdoor
determination method (S24).
[0181] Meanwhile, in S23, if the emission source number N is less
than the minimum emission source number M, it can be decided that
indoor/outdoor determination based on the first indoor/outdoor
determination method is impossible, and the second indoor/outdoor
determination component 56 executes indoor/outdoor determination
based on the second indoor/outdoor determination method as follows.
The second indoor/outdoor determination component 56 extracts from
the determination database 51 combined information including all of
the emission source identification information included in the MR,
and sets the lowest value of the number of emission sources
included in the extracted combined information as the minimum
emission source number Q (S25).
[0182] Then, the second indoor/outdoor determination component 56
determines whether or not the emission source number N is equal to
or greater than the minimum emission source number Q (S26). In S26,
if the emission source number N is equal to or greater than the
minimum emission source number M, it can be decided that the
cellular terminal 20 has received signals from at least the minimum
emission source number M of emission sources, so it is determined
that the cellular terminal 20 is outdoors (S28).
[0183] On the other hand, if in S26 the emission source number N is
less than the minimum emission source number M, it is determined
whether or not the emission source number N is less than the
minimum emission source number P at which indoor/outdoor
determination based on the second indoor/outdoor determination
method is possible (S31), and if the emission source number N is
less than the minimum emission source number P, it is determined
that indoor/outdoor determination based on the second
indoor/outdoor determination method is impossible (S33). On the
other hand, if the emission source number N is equal to or greater
than the minimum emission source number P in S31, it can be decided
that indoor/outdoor determination based on the second
indoor/outdoor determination method is possible, but the cellular
terminal 20 has not received signals from at least the minimum
emission source number M of emission sources, and the reception
state is poor, so it is determined that the cellular terminal 20 is
indoors (S32).
[0184] As discussed above, a determination result as to whether the
cellular terminal 20 is indoors or outdoors, or whether it cannot
be determined, can be quickly obtained by the indoor/outdoor
determination processing in FIG. 10.
Second Modification Example
[0185] As shown in FIG. 15, the indoor/outdoor determination
component 124, 134 in the second modification example comprises the
same determination database 51, reception component 52, and
specification component 53 as in the above embodiment, as well as a
setting component 57 and a determination controller 58. Of these,
the setting component 57 extracts from the determination database
51 combined information including all of the emission source
identification information included in the MR, and sets the lowest
value of the number of emission sources included in the extracted
combined information as the minimum emission source number Q. The
determination controller 58 performs indoor/outdoor determination
by the procedure discussed below, on the basis of the emission
source number N, the minimum emission source number Q, and the
minimum emission source number P at which indoor/outdoor
determination is possible.
[0186] The indoor/outdoor determination processing (indoor/outdoor
determination method) in the second modification example is
expressed by the flowchart in FIG. 16. Specifically, the reception
component 52 of the indoor/outdoor determination component 124, 134
receives from the cellular terminal 20 MR including the emission
source identification information for the received signal (S21 in
FIG. 16), and the specification component 53 counts the number of
pieces of emission source identification information included in
the received MR and thereby specifies the emission source number N
of the received signal (S22). Then, the setting component 57
extracts from the determination database 51 combined information
including all of the emission source identification information
included in the MR, and sets the lowest number of emission sources
included in the extracted combined information as the minimum
emission source number Q (S25).
[0187] Next, the determination controller 58 determines whether or
not the emission source number N is equal to or greater than the
minimum emission source number Q (S26). If the emission source
number N is equal to or greater than the minimum emission source
number M in S26, it can be decided that the cellular terminal 20
has received a signal from at least the minimum emission source
number M of emission sources, so it is determined that the cellular
terminal 20 is outdoors (S28).
[0188] On the other hand, if the emission source number N is less
than the minimum emission source number M in S26, it is determined
whether or not the emission source number N is less than the
minimum emission source number P at which indoor/outdoor
determination based on the second indoor/outdoor determination
method is possible (S31), and if the emission source number N is
less than the minimum emission source number P, it is determined
that indoor/outdoor determination based on the second
indoor/outdoor determination method is impossible (S33). On the
other hand, if in S31 the emission source number N is equal to or
greater than the minimum emission source number P, it is determined
that indoor/outdoor determination is possible on the basis of the
second indoor/outdoor determination method, but that the cellular
terminal 20 is indoors since it can be decided that the cellular
terminal 20 has not received a signal from at least the minimum
emission source number M of emission sources, and the reception
state is inferior (S32).
[0189] As discussed above, a determination result as to whether the
cellular terminal 20 is indoors or outdoors, or whether it cannot
be determined, can be quickly obtained by the indoor/outdoor
determination processing in FIG. 16. The indoor/outdoor
determination with respect to the cellular terminal 20 performed by
the indoor/outdoor determination component 124, 134 is not
necessarily limited to the method discussed above, and any method
can be used as long as it makes use of reception state information
indicating the reception state of radio waves at the cellular
terminal 20.
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